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From maximebeauche...@apache.org
Subject [incubator-superset] branch master updated: [flake8] Resolving Q??? errors (#3847)
Date Tue, 14 Nov 2017 05:06:54 GMT
This is an automated email from the ASF dual-hosted git repository.

maximebeauchemin pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-superset.git


The following commit(s) were added to refs/heads/master by this push:
     new ac57780  [flake8] Resolving Q??? errors (#3847)
ac57780 is described below

commit ac577806071c415eda071aad466322e37eb5b81b
Author: John Bodley <4567245+john-bodley@users.noreply.github.com>
AuthorDate: Mon Nov 13 21:06:51 2017 -0800

    [flake8] Resolving Q??? errors (#3847)
---
 setup.py                            |  14 +-
 superset/__init__.py                |  14 +-
 superset/cli.py                     | 106 +++---
 superset/config.py                  |   8 +-
 superset/connectors/base/models.py  |   6 +-
 superset/connectors/base/views.py   |   4 +-
 superset/connectors/druid/models.py | 128 +++----
 superset/connectors/druid/views.py  | 180 +++++-----
 superset/connectors/sqla/models.py  |  54 +--
 superset/connectors/sqla/views.py   | 220 ++++++------
 superset/db_engine_specs.py         | 224 ++++++-------
 superset/db_engines/hive.py         |   2 +-
 superset/db_engines/presto.py       |   6 +-
 superset/legacy.py                  |   2 +-
 superset/models/core.py             |  40 +--
 superset/models/helpers.py          |   4 +-
 superset/models/sql_lab.py          |   2 +-
 superset/security.py                |  18 +-
 superset/sql_lab.py                 |  32 +-
 superset/sql_parse.py               |   6 +-
 superset/stats_logger.py            |   8 +-
 superset/utils.py                   |  62 ++--
 superset/views/annotations.py       |  26 +-
 superset/views/base.py              |  38 +--
 superset/views/core.py              | 646 ++++++++++++++++++------------------
 superset/views/sql_lab.py           |  14 +-
 superset/viz.py                     | 467 +++++++++++++-------------
 tests/access_tests.py               |   4 +-
 tests/base_tests.py                 |  16 +-
 tests/celery_tests.py               |  57 ++--
 tests/core_tests.py                 | 142 ++++----
 tests/druid_tests.py                | 130 ++++----
 tests/import_export_tests.py        |  32 +-
 tests/sql_parse_tests.py            | 112 +++----
 tests/sqllab_tests.py               |  20 +-
 tests/utils_tests.py                |   6 +-
 tox.ini                             |   3 -
 37 files changed, 1424 insertions(+), 1429 deletions(-)

diff --git a/setup.py b/setup.py
index 217a070..ec12dea 100644
--- a/setup.py
+++ b/setup.py
@@ -16,7 +16,7 @@ def get_git_sha():
         s = str(subprocess.check_output(['git', 'rev-parse', 'HEAD']))
         return s.strip()
     except Exception:
-        return ""
+        return ''
 
 
 GIT_SHA = get_git_sha()
@@ -24,10 +24,10 @@ version_info = {
     'GIT_SHA': GIT_SHA,
     'version': version_string,
 }
-print("-==-" * 15)
-print("VERSION: " + version_string)
-print("GIT SHA: " + GIT_SHA)
-print("-==-" * 15)
+print('-==-' * 15)
+print('VERSION: ' + version_string)
+print('GIT SHA: ' + GIT_SHA)
+print('-==-' * 15)
 
 with open(os.path.join(PACKAGE_DIR, 'version_info.json'), 'w') as version_file:
     json.dump(version_info, version_file)
@@ -36,8 +36,8 @@ with open(os.path.join(PACKAGE_DIR, 'version_info.json'), 'w') as version_file:
 setup(
     name='superset',
     description=(
-        "A interactive data visualization platform build on SqlAlchemy "
-        "and druid.io"),
+        'A interactive data visualization platform build on SqlAlchemy '
+        'and druid.io'),
     version=version_string,
     packages=find_packages(),
     include_package_data=True,
diff --git a/superset/__init__.py b/superset/__init__.py
index 6c1c906..099edc1 100644
--- a/superset/__init__.py
+++ b/superset/__init__.py
@@ -42,7 +42,7 @@ def parse_manifest_json():
         with open(MANIFEST_FILE, 'r') as f:
             manifest = json.load(f)
     except Exception:
-        print("no manifest file found at " + MANIFEST_FILE)
+        print('no manifest file found at ' + MANIFEST_FILE)
 
 
 def get_manifest_file(filename):
@@ -66,7 +66,7 @@ for bp in conf.get('BLUEPRINTS'):
         print("Registering blueprint: '{}'".format(bp.name))
         app.register_blueprint(bp)
     except Exception as e:
-        print("blueprint registration failed")
+        print('blueprint registration failed')
         logging.exception(e)
 
 if conf.get('SILENCE_FAB'):
@@ -91,7 +91,7 @@ utils.pessimistic_connection_handling(db.engine)
 cache = utils.setup_cache(app, conf.get('CACHE_CONFIG'))
 tables_cache = utils.setup_cache(app, conf.get('TABLE_NAMES_CACHE_CONFIG'))
 
-migrate = Migrate(app, db, directory=APP_DIR + "/migrations")
+migrate = Migrate(app, db, directory=APP_DIR + '/migrations')
 
 # Logging configuration
 logging.basicConfig(format=app.config.get('LOG_FORMAT'))
@@ -149,15 +149,15 @@ appbuilder = AppBuilder(
     db.session,
     base_template='superset/base.html',
     indexview=MyIndexView,
-    security_manager_class=app.config.get("CUSTOM_SECURITY_MANAGER"))
+    security_manager_class=app.config.get('CUSTOM_SECURITY_MANAGER'))
 
 sm = appbuilder.sm
 
-results_backend = app.config.get("RESULTS_BACKEND")
+results_backend = app.config.get('RESULTS_BACKEND')
 
 # Registering sources
-module_datasource_map = app.config.get("DEFAULT_MODULE_DS_MAP")
-module_datasource_map.update(app.config.get("ADDITIONAL_MODULE_DS_MAP"))
+module_datasource_map = app.config.get('DEFAULT_MODULE_DS_MAP')
+module_datasource_map.update(app.config.get('ADDITIONAL_MODULE_DS_MAP'))
 ConnectorRegistry.register_sources(module_datasource_map)
 
 from superset import views  # noqa
diff --git a/superset/cli.py b/superset/cli.py
index 37a0f63..540bea8 100755
--- a/superset/cli.py
+++ b/superset/cli.py
@@ -29,38 +29,38 @@ def init():
 
 @manager.option(
     '-d', '--debug', action='store_true',
-    help="Start the web server in debug mode")
+    help='Start the web server in debug mode')
 @manager.option(
     '-n', '--no-reload', action='store_false', dest='no_reload',
-    default=config.get("FLASK_USE_RELOAD"),
+    default=config.get('FLASK_USE_RELOAD'),
     help="Don't use the reloader in debug mode")
 @manager.option(
-    '-a', '--address', default=config.get("SUPERSET_WEBSERVER_ADDRESS"),
-    help="Specify the address to which to bind the web server")
+    '-a', '--address', default=config.get('SUPERSET_WEBSERVER_ADDRESS'),
+    help='Specify the address to which to bind the web server')
 @manager.option(
-    '-p', '--port', default=config.get("SUPERSET_WEBSERVER_PORT"),
-    help="Specify the port on which to run the web server")
+    '-p', '--port', default=config.get('SUPERSET_WEBSERVER_PORT'),
+    help='Specify the port on which to run the web server')
 @manager.option(
     '-w', '--workers',
-    default=config.get("SUPERSET_WORKERS", 2),
-    help="Number of gunicorn web server workers to fire up")
+    default=config.get('SUPERSET_WORKERS', 2),
+    help='Number of gunicorn web server workers to fire up')
 @manager.option(
-    '-t', '--timeout', default=config.get("SUPERSET_WEBSERVER_TIMEOUT"),
-    help="Specify the timeout (seconds) for the gunicorn web server")
+    '-t', '--timeout', default=config.get('SUPERSET_WEBSERVER_TIMEOUT'),
+    help='Specify the timeout (seconds) for the gunicorn web server')
 @manager.option(
-    '-s', '--socket', default=config.get("SUPERSET_WEBSERVER_SOCKET"),
-    help="Path to a UNIX socket as an alternative to address:port, e.g. "
-         "/var/run/superset.sock. "
-         "Will override the address and port values.")
+    '-s', '--socket', default=config.get('SUPERSET_WEBSERVER_SOCKET'),
+    help='Path to a UNIX socket as an alternative to address:port, e.g. '
+         '/var/run/superset.sock. '
+         'Will override the address and port values.')
 def runserver(debug, no_reload, address, port, timeout, workers, socket):
     """Starts a Superset web server."""
-    debug = debug or config.get("DEBUG")
+    debug = debug or config.get('DEBUG')
     if debug:
         print(Fore.BLUE + '-=' * 20)
         print(
-            Fore.YELLOW + "Starting Superset server in " +
-            Fore.RED + "DEBUG" +
-            Fore.YELLOW + " mode")
+            Fore.YELLOW + 'Starting Superset server in ' +
+            Fore.RED + 'DEBUG' +
+            Fore.YELLOW + ' mode')
         print(Fore.BLUE + '-=' * 20)
         print(Style.RESET_ALL)
         app.run(
@@ -70,16 +70,16 @@ def runserver(debug, no_reload, address, port, timeout, workers, socket):
             debug=True,
             use_reloader=no_reload)
     else:
-        addr_str = " unix:{socket} " if socket else" {address}:{port} "
+        addr_str = ' unix:{socket} ' if socket else' {address}:{port} '
         cmd = (
-            "gunicorn "
-            "-w {workers} "
-            "--timeout {timeout} "
-            "-b " + addr_str +
-            "--limit-request-line 0 "
-            "--limit-request-field_size 0 "
-            "superset:app").format(**locals())
-        print(Fore.GREEN + "Starting server with command: ")
+            'gunicorn '
+            '-w {workers} '
+            '--timeout {timeout} '
+            '-b ' + addr_str +
+            '--limit-request-line 0 '
+            '--limit-request-field_size 0 '
+            'superset:app').format(**locals())
+        print(Fore.GREEN + 'Starting server with command: ')
         print(Fore.YELLOW + cmd)
         print(Style.RESET_ALL)
         Popen(cmd, shell=True).wait()
@@ -87,69 +87,69 @@ def runserver(debug, no_reload, address, port, timeout, workers, socket):
 
 @manager.option(
     '-v', '--verbose', action='store_true',
-    help="Show extra information")
+    help='Show extra information')
 def version(verbose):
     """Prints the current version number"""
     print(Fore.BLUE + '-=' * 15)
-    print(Fore.YELLOW + "Superset " + Fore.CYAN + "{version}".format(
+    print(Fore.YELLOW + 'Superset ' + Fore.CYAN + '{version}'.format(
         version=config.get('VERSION_STRING')))
     print(Fore.BLUE + '-=' * 15)
     if verbose:
-        print("[DB] : " + "{}".format(db.engine))
+        print('[DB] : ' + '{}'.format(db.engine))
     print(Style.RESET_ALL)
 
 
 @manager.option(
     '-t', '--load-test-data', action='store_true',
-    help="Load additional test data")
+    help='Load additional test data')
 def load_examples(load_test_data):
     """Loads a set of Slices and Dashboards and a supporting dataset """
     from superset import data
-    print("Loading examples into {}".format(db))
+    print('Loading examples into {}'.format(db))
 
     data.load_css_templates()
 
-    print("Loading energy related dataset")
+    print('Loading energy related dataset')
     data.load_energy()
 
     print("Loading [World Bank's Health Nutrition and Population Stats]")
     data.load_world_bank_health_n_pop()
 
-    print("Loading [Birth names]")
+    print('Loading [Birth names]')
     data.load_birth_names()
 
-    print("Loading [Random time series data]")
+    print('Loading [Random time series data]')
     data.load_random_time_series_data()
 
-    print("Loading [Random long/lat data]")
+    print('Loading [Random long/lat data]')
     data.load_long_lat_data()
 
-    print("Loading [Country Map data]")
+    print('Loading [Country Map data]')
     data.load_country_map_data()
 
-    print("Loading [Multiformat time series]")
+    print('Loading [Multiformat time series]')
     data.load_multiformat_time_series_data()
 
-    print("Loading [Misc Charts] dashboard")
+    print('Loading [Misc Charts] dashboard')
     data.load_misc_dashboard()
 
     if load_test_data:
-        print("Loading [Unicode test data]")
+        print('Loading [Unicode test data]')
         data.load_unicode_test_data()
 
 
 @manager.option(
     '-d', '--datasource',
     help=(
-        "Specify which datasource name to load, if omitted, all "
-        "datasources will be refreshed"
+        'Specify which datasource name to load, if omitted, all '
+        'datasources will be refreshed'
     ),
 )
 @manager.option(
     '-m', '--merge',
     help=(
         "Specify using 'merge' property during operation. "
-        "Default value is False "
+        'Default value is False '
     ),
 )
 def refresh_druid(datasource, merge):
@@ -167,8 +167,8 @@ def refresh_druid(datasource, merge):
             logging.exception(e)
         cluster.metadata_last_refreshed = datetime.now()
         print(
-            "Refreshed metadata from cluster "
-            "[" + cluster.cluster_name + "]")
+            'Refreshed metadata from cluster '
+            '[' + cluster.cluster_name + ']')
     session.commit()
 
 
@@ -188,14 +188,14 @@ def update_datasources_cache():
 @manager.option(
     '-w', '--workers',
     type=int,
-    help="Number of celery server workers to fire up")
+    help='Number of celery server workers to fire up')
 def worker(workers):
     """Starts a Superset worker for async SQL query execution."""
     if workers:
         celery_app.conf.update(CELERYD_CONCURRENCY=workers)
-    elif config.get("SUPERSET_CELERY_WORKERS"):
+    elif config.get('SUPERSET_CELERY_WORKERS'):
         celery_app.conf.update(
-            CELERYD_CONCURRENCY=config.get("SUPERSET_CELERY_WORKERS"))
+            CELERYD_CONCURRENCY=config.get('SUPERSET_CELERY_WORKERS'))
 
     worker = celery_app.Worker(optimization='fair')
     worker.start()
@@ -216,12 +216,12 @@ def flower(port, address):
     broker"""
     BROKER_URL = celery_app.conf.BROKER_URL
     cmd = (
-        "celery flower "
-        "--broker={BROKER_URL} "
-        "--port={port} "
-        "--address={address} "
+        'celery flower '
+        '--broker={BROKER_URL} '
+        '--port={port} '
+        '--address={address} '
     ).format(**locals())
-    print(Fore.GREEN + "Starting a Celery Flower instance")
+    print(Fore.GREEN + 'Starting a Celery Flower instance')
     print(Fore.BLUE + '-=' * 40)
     print(Fore.YELLOW + cmd)
     print(Fore.BLUE + '-=' * 40)
diff --git a/superset/config.py b/superset/config.py
index 95ee3b0..2d168a9 100644
--- a/superset/config.py
+++ b/superset/config.py
@@ -92,10 +92,10 @@ ENABLE_PROXY_FIX = False
 # GLOBALS FOR APP Builder
 # ------------------------------
 # Uncomment to setup Your App name
-APP_NAME = "Superset"
+APP_NAME = 'Superset'
 
 # Uncomment to setup an App icon
-APP_ICON = "/static/assets/images/superset-logo@2x.png"
+APP_ICON = '/static/assets/images/superset-logo@2x.png'
 
 # Druid query timezone
 # tz.tzutc() : Using utc timezone
@@ -239,7 +239,7 @@ INTERVAL = 1
 BACKUP_COUNT = 30
 
 # Set this API key to enable Mapbox visualizations
-MAPBOX_API_KEY = ""
+MAPBOX_API_KEY = ''
 
 # Maximum number of rows returned in the SQL editor
 SQL_MAX_ROW = 1000000
@@ -329,7 +329,7 @@ SILENCE_FAB = True
 
 # The link to a page containing common errors and their resolutions
 # It will be appended at the bottom of sql_lab errors.
-TROUBLESHOOTING_LINK = ""
+TROUBLESHOOTING_LINK = ''
 
 
 # Integrate external Blueprints to the app by passing them to your
diff --git a/superset/connectors/base/models.py b/superset/connectors/base/models.py
index 0a03366..8042ac9 100644
--- a/superset/connectors/base/models.py
+++ b/superset/connectors/base/models.py
@@ -60,7 +60,7 @@ class BaseDatasource(AuditMixinNullable, ImportMixin):
     @property
     def uid(self):
         """Unique id across datasource types"""
-        return "{self.id}__{self.type}".format(**locals())
+        return '{self.id}__{self.type}'.format(**locals())
 
     @property
     def column_names(self):
@@ -72,7 +72,7 @@ class BaseDatasource(AuditMixinNullable, ImportMixin):
 
     @property
     def main_dttm_col(self):
-        return "timestamp"
+        return 'timestamp'
 
     @property
     def connection(self):
@@ -105,7 +105,7 @@ class BaseDatasource(AuditMixinNullable, ImportMixin):
         if self.default_endpoint:
             return self.default_endpoint
         else:
-            return "/superset/explore/{obj.type}/{obj.id}/".format(obj=self)
+            return '/superset/explore/{obj.type}/{obj.id}/'.format(obj=self)
 
     @property
     def column_formats(self):
diff --git a/superset/connectors/base/views.py b/superset/connectors/base/views.py
index 97a40eb..2794d18 100644
--- a/superset/connectors/base/views.py
+++ b/superset/connectors/base/views.py
@@ -8,6 +8,6 @@ class DatasourceModelView(SupersetModelView):
     def pre_delete(self, obj):
         if obj.slices:
             raise SupersetException(Markup(
-                "Cannot delete a datasource that has slices attached to it."
+                'Cannot delete a datasource that has slices attached to it.'
                 "Here's the list of associated slices: " +
-                "".join([o.slice_link for o in obj.slices])))
+                ''.join([o.slice_link for o in obj.slices])))
diff --git a/superset/connectors/druid/models.py b/superset/connectors/druid/models.py
index afbfb26..4c8a016 100644
--- a/superset/connectors/druid/models.py
+++ b/superset/connectors/druid/models.py
@@ -33,7 +33,7 @@ from superset.utils import (
     DimSelector, DTTM_ALIAS, flasher, MetricPermException,
 )
 
-DRUID_TZ = conf.get("DRUID_TZ")
+DRUID_TZ = conf.get('DRUID_TZ')
 
 
 # Function wrapper because bound methods cannot
@@ -65,7 +65,7 @@ class DruidCluster(Model, AuditMixinNullable):
     """ORM object referencing the Druid clusters"""
 
     __tablename__ = 'clusters'
-    type = "druid"
+    type = 'druid'
 
     id = Column(Integer, primary_key=True)
     verbose_name = Column(String(250), unique=True)
@@ -86,21 +86,21 @@ class DruidCluster(Model, AuditMixinNullable):
 
     def get_pydruid_client(self):
         cli = PyDruid(
-            "http://{0}:{1}/".format(self.broker_host, self.broker_port),
+            'http://{0}:{1}/'.format(self.broker_host, self.broker_port),
             self.broker_endpoint)
         return cli
 
     def get_datasources(self):
         endpoint = (
-            "http://{obj.coordinator_host}:{obj.coordinator_port}/"
-            "{obj.coordinator_endpoint}/datasources"
+            'http://{obj.coordinator_host}:{obj.coordinator_port}/'
+            '{obj.coordinator_endpoint}/datasources'
         ).format(obj=self)
 
         return json.loads(requests.get(endpoint).text)
 
     def get_druid_version(self):
         endpoint = (
-            "http://{obj.coordinator_host}:{obj.coordinator_port}/status"
+            'http://{obj.coordinator_host}:{obj.coordinator_port}/status'
         ).format(obj=self)
         return json.loads(requests.get(endpoint).text)['version']
 
@@ -144,11 +144,11 @@ class DruidCluster(Model, AuditMixinNullable):
                 with session.no_autoflush:
                     session.add(datasource)
                 flasher(
-                    "Adding new datasource [{}]".format(ds_name), 'success')
+                    'Adding new datasource [{}]'.format(ds_name), 'success')
                 ds_map[ds_name] = datasource
             elif refreshAll:
                 flasher(
-                    "Refreshing datasource [{}]".format(ds_name), 'info')
+                    'Refreshing datasource [{}]'.format(ds_name), 'info')
             else:
                 del ds_map[ds_name]
                 continue
@@ -200,7 +200,7 @@ class DruidCluster(Model, AuditMixinNullable):
 
     @property
     def perm(self):
-        return "[{obj.cluster_name}].(id:{obj.id})".format(obj=self)
+        return '[{obj.cluster_name}].(id:{obj.id})'.format(obj=self)
 
     def get_perm(self):
         return self.perm
@@ -390,7 +390,7 @@ class DruidMetric(Model, BaseMetric):
     @property
     def perm(self):
         return (
-            "{parent_name}.[{obj.metric_name}](id:{obj.id})"
+            '{parent_name}.[{obj.metric_name}](id:{obj.id})'
         ).format(obj=self,
                  parent_name=self.datasource.full_name,
                  ) if self.datasource else None
@@ -410,13 +410,13 @@ class DruidDatasource(Model, BaseDatasource):
 
     __tablename__ = 'datasources'
 
-    type = "druid"
-    query_langtage = "json"
+    type = 'druid'
+    query_langtage = 'json'
     cluster_class = DruidCluster
     metric_class = DruidMetric
     column_class = DruidColumn
 
-    baselink = "druiddatasourcemodelview"
+    baselink = 'druiddatasourcemodelview'
 
     # Columns
     datasource_name = Column(String(255), unique=True)
@@ -469,8 +469,8 @@ class DruidDatasource(Model, BaseDatasource):
 
     def get_perm(self):
         return (
-            "[{obj.cluster_name}].[{obj.datasource_name}]"
-            "(id:{obj.id})").format(obj=self)
+            '[{obj.cluster_name}].[{obj.datasource_name}]'
+            '(id:{obj.id})').format(obj=self)
 
     @property
     def link(self):
@@ -485,13 +485,13 @@ class DruidDatasource(Model, BaseDatasource):
     @property
     def time_column_grains(self):
         return {
-            "time_columns": [
+            'time_columns': [
                 'all', '5 seconds', '30 seconds', '1 minute',
                 '5 minutes', '1 hour', '6 hour', '1 day', '7 days',
                 'week', 'week_starting_sunday', 'week_ending_saturday',
                 'month',
             ],
-            "time_grains": ['now'],
+            'time_grains': ['now'],
         }
 
     def __repr__(self):
@@ -499,7 +499,7 @@ class DruidDatasource(Model, BaseDatasource):
 
     @renders('datasource_name')
     def datasource_link(self):
-        url = "/superset/explore/{obj.type}/{obj.id}/".format(obj=self)
+        url = '/superset/explore/{obj.type}/{obj.id}/'.format(obj=self)
         name = escape(self.datasource_name)
         return Markup('<a href="{url}">{name}</a>'.format(**locals()))
 
@@ -561,7 +561,7 @@ class DruidDatasource(Model, BaseDatasource):
 
     def latest_metadata(self):
         """Returns segment metadata from the latest segment"""
-        logging.info("Syncing datasource [{}]".format(self.datasource_name))
+        logging.info('Syncing datasource [{}]'.format(self.datasource_name))
         client = self.cluster.get_pydruid_client()
         results = client.time_boundary(datasource=self.datasource_name)
         if not results:
@@ -585,7 +585,7 @@ class DruidDatasource(Model, BaseDatasource):
                 merge=self.merge_flag,
                 analysisTypes=[])
         except Exception as e:
-            logging.warning("Failed first attempt to get latest segment")
+            logging.warning('Failed first attempt to get latest segment')
             logging.exception(e)
         if not segment_metadata:
             # if no segments in the past 7 days, look at all segments
@@ -601,7 +601,7 @@ class DruidDatasource(Model, BaseDatasource):
                     merge=self.merge_flag,
                     analysisTypes=[])
             except Exception as e:
-                logging.warning("Failed 2nd attempt to get latest segment")
+                logging.warning('Failed 2nd attempt to get latest segment')
                 logging.exception(e)
         if segment_metadata:
             return segment_metadata[-1]['columns']
@@ -669,7 +669,7 @@ class DruidDatasource(Model, BaseDatasource):
                     groupby=True,
                     filterable=True,
                     # TODO: fetch type from Hive.
-                    type="STRING",
+                    type='STRING',
                     datasource=datasource,
                 )
                 session.add(col_obj)
@@ -678,20 +678,20 @@ class DruidDatasource(Model, BaseDatasource):
             session.query(DruidMetric)
             .filter(DruidMetric.datasource_name == druid_config['name'])
             .filter(or_(DruidMetric.metric_name == spec['name']
-                    for spec in druid_config["metrics_spec"]))
+                    for spec in druid_config['metrics_spec']))
         )
         metric_objs = {metric.metric_name: metric for metric in metric_objs}
-        for metric_spec in druid_config["metrics_spec"]:
-            metric_name = metric_spec["name"]
-            metric_type = metric_spec["type"]
+        for metric_spec in druid_config['metrics_spec']:
+            metric_name = metric_spec['name']
+            metric_type = metric_spec['type']
             metric_json = json.dumps(metric_spec)
 
-            if metric_type == "count":
-                metric_type = "longSum"
+            if metric_type == 'count':
+                metric_type = 'longSum'
                 metric_json = json.dumps({
-                    "type": "longSum",
-                    "name": metric_name,
-                    "fieldName": metric_name,
+                    'type': 'longSum',
+                    'name': metric_name,
+                    'fieldName': metric_name,
                 })
 
             metric_obj = metric_objs.get(metric_name, None)
@@ -699,11 +699,11 @@ class DruidDatasource(Model, BaseDatasource):
                 metric_obj = DruidMetric(
                     metric_name=metric_name,
                     metric_type=metric_type,
-                    verbose_name="%s(%s)" % (metric_type, metric_name),
+                    verbose_name='%s(%s)' % (metric_type, metric_name),
                     datasource=datasource,
                     json=metric_json,
                     description=(
-                        "Imported from the airolap config dir for %s" %
+                        'Imported from the airolap config dir for %s' %
                         druid_config['name']),
                 )
                 session.add(metric_obj)
@@ -823,7 +823,7 @@ class DruidDatasource(Model, BaseDatasource):
                     )
                 elif mconf.get('type') == 'arithmetic':
                     post_aggs[metric_name] = Postaggregator(
-                        mconf.get('fn', "/"),
+                        mconf.get('fn', '/'),
                         mconf.get('fields', []),
                         mconf.get('name', ''))
                 else:
@@ -844,11 +844,11 @@ class DruidDatasource(Model, BaseDatasource):
 
         qry = dict(
             datasource=self.datasource_name,
-            granularity="all",
+            granularity='all',
             intervals=from_dttm.isoformat() + '/' + datetime.now().isoformat(),
-            aggregations=dict(count=count("count")),
+            aggregations=dict(count=count('count')),
             dimension=column_name,
-            metric="count",
+            metric='count',
             threshold=limit,
         )
 
@@ -870,16 +870,16 @@ class DruidDatasource(Model, BaseDatasource):
                     f = Dimension(dim) == row[dim]
                     fields.append(f)
                 if len(fields) > 1:
-                    term = Filter(type="and", fields=fields)
+                    term = Filter(type='and', fields=fields)
                     new_filters.append(term)
                 elif fields:
                     new_filters.append(fields[0])
             if new_filters:
-                ff = Filter(type="or", fields=new_filters)
+                ff = Filter(type='or', fields=new_filters)
                 if not dim_filter:
                     ret = ff
                 else:
-                    ret = Filter(type="and", fields=[ff, dim_filter])
+                    ret = Filter(type='and', fields=[ff, dim_filter])
         return ret
 
     def run_query(  # noqa / druid
@@ -913,7 +913,7 @@ class DruidDatasource(Model, BaseDatasource):
         to_dttm = to_dttm.replace(tzinfo=DRUID_TZ)
         timezone = from_dttm.tzname()
 
-        query_str = ""
+        query_str = ''
         metrics_dict = {m.metric_name: m for m in self.metrics}
 
         columns_dict = {c.column_name: c for c in self.columns}
@@ -936,7 +936,7 @@ class DruidDatasource(Model, BaseDatasource):
 
         if rejected_metrics:
             raise MetricPermException(
-                "Access to the metrics denied: " + ', '.join(rejected_metrics),
+                'Access to the metrics denied: ' + ', '.join(rejected_metrics),
             )
 
         # the dimensions list with dimensionSpecs expanded
@@ -969,7 +969,7 @@ class DruidDatasource(Model, BaseDatasource):
         having_filters = self.get_having_filters(extras.get('having_druid'))
         if having_filters:
             qry['having'] = having_filters
-        order_direction = "descending" if order_desc else "ascending"
+        order_direction = 'descending' if order_desc else 'ascending'
         if len(groupby) == 0 and not having_filters:
             del qry['dimensions']
             client.timeseries(**qry)
@@ -987,17 +987,17 @@ class DruidDatasource(Model, BaseDatasource):
                 order_by = list(qry['aggregations'].keys())[0]
             # Limit on the number of timeseries, doing a two-phases query
             pre_qry = deepcopy(qry)
-            pre_qry['granularity'] = "all"
+            pre_qry['granularity'] = 'all'
             pre_qry['threshold'] = min(row_limit,
                                        timeseries_limit or row_limit)
             pre_qry['metric'] = order_by
             pre_qry['dimension'] = dim
             del pre_qry['dimensions']
             client.topn(**pre_qry)
-            query_str += "// Two phase query\n// Phase 1\n"
+            query_str += '// Two phase query\n// Phase 1\n'
             query_str += json.dumps(
                 client.query_builder.last_query.query_dict, indent=2)
-            query_str += "\n"
+            query_str += '\n'
             if phase == 1:
                 return query_str
             query_str += (
@@ -1023,23 +1023,23 @@ class DruidDatasource(Model, BaseDatasource):
                     order_by = timeseries_limit_metric
                 # Limit on the number of timeseries, doing a two-phases query
                 pre_qry = deepcopy(qry)
-                pre_qry['granularity'] = "all"
+                pre_qry['granularity'] = 'all'
                 pre_qry['limit_spec'] = {
-                    "type": "default",
-                    "limit": min(timeseries_limit, row_limit),
+                    'type': 'default',
+                    'limit': min(timeseries_limit, row_limit),
                     'intervals': (
                         inner_from_dttm.isoformat() + '/' +
                         inner_to_dttm.isoformat()),
-                    "columns": [{
-                        "dimension": order_by,
-                        "direction": order_direction,
+                    'columns': [{
+                        'dimension': order_by,
+                        'direction': order_direction,
                     }],
                 }
                 client.groupby(**pre_qry)
-                query_str += "// Two phase query\n// Phase 1\n"
+                query_str += '// Two phase query\n// Phase 1\n'
                 query_str += json.dumps(
                     client.query_builder.last_query.query_dict, indent=2)
-                query_str += "\n"
+                query_str += '\n'
                 if phase == 1:
                     return query_str
                 query_str += (
@@ -1053,12 +1053,12 @@ class DruidDatasource(Model, BaseDatasource):
                 qry['limit_spec'] = None
             if row_limit:
                 qry['limit_spec'] = {
-                    "type": "default",
-                    "limit": row_limit,
-                    "columns": [{
-                        "dimension": (
+                    'type': 'default',
+                    'limit': row_limit,
+                    'columns': [{
+                        'dimension': (
                             metrics[0] if metrics else self.metrics[0]),
-                        "direction": order_direction,
+                        'direction': order_direction,
                     }],
                 }
             client.groupby(**qry)
@@ -1074,7 +1074,7 @@ class DruidDatasource(Model, BaseDatasource):
         df = client.export_pandas()
 
         if df is None or df.size == 0:
-            raise Exception(_("No data was returned."))
+            raise Exception(_('No data was returned.'))
         df.columns = [
             DTTM_ALIAS if c == 'timestamp' else c for c in df.columns]
 
@@ -1120,7 +1120,7 @@ class DruidDatasource(Model, BaseDatasource):
             cond = None
             if op in ('in', 'not in'):
                 eq = [
-                    types.replace("'", '').strip()
+                    types.replace('"', '').strip()
                     if isinstance(types, string_types)
                     else types
                     for types in eq]
@@ -1149,13 +1149,13 @@ class DruidDatasource(Model, BaseDatasource):
                 else:
                     for s in eq:
                         fields.append(Dimension(col) == s)
-                    cond = Filter(type="or", fields=fields)
+                    cond = Filter(type='or', fields=fields)
 
                 if op == 'not in':
                     cond = ~cond
 
             elif op == 'regex':
-                cond = Filter(type="regex", pattern=eq, dimension=col)
+                cond = Filter(type='regex', pattern=eq, dimension=col)
             elif op == '>=':
                 cond = Bound(col, eq, None, alphaNumeric=is_numeric_col)
             elif op == '<=':
@@ -1172,7 +1172,7 @@ class DruidDatasource(Model, BaseDatasource):
                 )
 
             if filters:
-                filters = Filter(type="and", fields=[
+                filters = Filter(type='and', fields=[
                     cond,
                     filters,
                 ])
diff --git a/superset/connectors/druid/views.py b/superset/connectors/druid/views.py
index 5293166..713a43c 100644
--- a/superset/connectors/druid/views.py
+++ b/superset/connectors/druid/views.py
@@ -37,27 +37,27 @@ class DruidColumnInlineView(CompactCRUDMixin, SupersetModelView):  # noqa
     can_delete = False
     page_size = 500
     label_columns = {
-        'column_name': _("Column"),
-        'type': _("Type"),
-        'datasource': _("Datasource"),
-        'groupby': _("Groupable"),
-        'filterable': _("Filterable"),
-        'count_distinct': _("Count Distinct"),
-        'sum': _("Sum"),
-        'min': _("Min"),
-        'max': _("Max"),
+        'column_name': _('Column'),
+        'type': _('Type'),
+        'datasource': _('Datasource'),
+        'groupby': _('Groupable'),
+        'filterable': _('Filterable'),
+        'count_distinct': _('Count Distinct'),
+        'sum': _('Sum'),
+        'min': _('Min'),
+        'max': _('Max'),
     }
     description_columns = {
         'filterable': _(
-            "Whether this column is exposed in the `Filters` section "
-            "of the explore view."),
+            'Whether this column is exposed in the `Filters` section '
+            'of the explore view.'),
         'dimension_spec_json': utils.markdown(
-            "this field can be used to specify  "
-            "a `dimensionSpec` as documented [here]"
-            "(http://druid.io/docs/latest/querying/dimensionspecs.html). "
-            "Make sure to input valid JSON and that the "
-            "`outputName` matches the `column_name` defined "
-            "above.",
+            'this field can be used to specify  '
+            'a `dimensionSpec` as documented [here]'
+            '(http://druid.io/docs/latest/querying/dimensionspecs.html). '
+            'Make sure to input valid JSON and that the '
+            '`outputName` matches the `column_name` defined '
+            'above.',
             True),
     }
 
@@ -91,23 +91,23 @@ class DruidMetricInlineView(CompactCRUDMixin, SupersetModelView):  # noqa
     }
     description_columns = {
         'metric_type': utils.markdown(
-            "use `postagg` as the metric type if you are defining a "
-            "[Druid Post Aggregation]"
-            "(http://druid.io/docs/latest/querying/post-aggregations.html)",
+            'use `postagg` as the metric type if you are defining a '
+            '[Druid Post Aggregation]'
+            '(http://druid.io/docs/latest/querying/post-aggregations.html)',
             True),
-        'is_restricted': _("Whether the access to this metric is restricted "
-                           "to certain roles. Only roles with the permission "
+        'is_restricted': _('Whether the access to this metric is restricted '
+                           'to certain roles. Only roles with the permission '
                            "'metric access on XXX (the name of this metric)' "
-                           "are allowed to access this metric"),
+                           'are allowed to access this metric'),
     }
     label_columns = {
-        'metric_name': _("Metric"),
-        'description': _("Description"),
-        'verbose_name': _("Verbose Name"),
-        'metric_type': _("Type"),
-        'json': _("JSON"),
-        'datasource': _("Druid Datasource"),
-        'warning_text': _("Warning Message"),
+        'metric_name': _('Metric'),
+        'description': _('Description'),
+        'verbose_name': _('Verbose Name'),
+        'metric_type': _('Type'),
+        'json': _('JSON'),
+        'datasource': _('Druid Datasource'),
+        'warning_text': _('Warning Message'),
     }
 
     def post_add(self, metric):
@@ -139,13 +139,13 @@ class DruidClusterModelView(SupersetModelView, DeleteMixin):  # noqa
     list_columns = ['cluster_name', 'metadata_last_refreshed']
     search_columns = ('cluster_name',)
     label_columns = {
-        'cluster_name': _("Cluster"),
-        'coordinator_host': _("Coordinator Host"),
-        'coordinator_port': _("Coordinator Port"),
-        'coordinator_endpoint': _("Coordinator Endpoint"),
-        'broker_host': _("Broker Host"),
-        'broker_port': _("Broker Port"),
-        'broker_endpoint': _("Broker Endpoint"),
+        'cluster_name': _('Cluster'),
+        'coordinator_host': _('Coordinator Host'),
+        'coordinator_port': _('Coordinator Port'),
+        'coordinator_endpoint': _('Coordinator Endpoint'),
+        'broker_host': _('Broker Host'),
+        'broker_port': _('Broker Port'),
+        'broker_endpoint': _('Broker Endpoint'),
     }
 
     def pre_add(self, cluster):
@@ -160,11 +160,11 @@ class DruidClusterModelView(SupersetModelView, DeleteMixin):  # noqa
 
 appbuilder.add_view(
     DruidClusterModelView,
-    name="Druid Clusters",
-    label=__("Druid Clusters"),
-    icon="fa-cubes",
-    category="Sources",
-    category_label=__("Sources"),
+    name='Druid Clusters',
+    label=__('Druid Clusters'),
+    icon='fa-cubes',
+    category='Sources',
+    category_label=__('Sources'),
     category_icon='fa-database',)
 
 
@@ -195,44 +195,44 @@ class DruidDatasourceModelView(DatasourceModelView, DeleteMixin):  # noqa
     base_order = ('datasource_name', 'asc')
     description_columns = {
         'slices': _(
-            "The list of slices associated with this table. By "
-            "altering this datasource, you may change how these associated "
-            "slices behave. "
-            "Also note that slices need to point to a datasource, so "
-            "this form will fail at saving if removing slices from a "
-            "datasource. If you want to change the datasource for a slice, "
+            'The list of slices associated with this table. By '
+            'altering this datasource, you may change how these associated '
+            'slices behave. '
+            'Also note that slices need to point to a datasource, so '
+            'this form will fail at saving if removing slices from a '
+            'datasource. If you want to change the datasource for a slice, '
             "overwrite the slice from the 'explore view'"),
-        'offset': _("Timezone offset (in hours) for this datasource"),
+        'offset': _('Timezone offset (in hours) for this datasource'),
         'description': Markup(
-            "Supports <a href='"
-            "https://daringfireball.net/projects/markdown/'>markdown</a>"),
+            'Supports <a href="'
+            'https://daringfireball.net/projects/markdown/">markdown</a>'),
         'fetch_values_from': _(
-            "Time expression to use as a predicate when retrieving "
-            "distinct values to populate the filter component. "
-            "Only applies when `Enable Filter Select` is on. If "
-            "you enter `7 days ago`, the distinct list of values in "
-            "the filter will be populated based on the distinct value over "
-            "the past week"),
+            'Time expression to use as a predicate when retrieving '
+            'distinct values to populate the filter component. '
+            'Only applies when `Enable Filter Select` is on. If '
+            'you enter `7 days ago`, the distinct list of values in '
+            'the filter will be populated based on the distinct value over '
+            'the past week'),
         'filter_select_enabled': _(
             "Whether to populate the filter's dropdown in the explore "
             "view's filter section with a list of distinct values fetched "
-            "from the backend on the fly"),
+            'from the backend on the fly'),
         'default_endpoint': _(
-            "Redirects to this endpoint when clicking on the datasource "
-            "from the datasource list"),
+            'Redirects to this endpoint when clicking on the datasource '
+            'from the datasource list'),
     }
     base_filters = [['id', DatasourceFilter, lambda: []]]
     label_columns = {
-        'slices': _("Associated Slices"),
-        'datasource_link': _("Data Source"),
-        'cluster': _("Cluster"),
-        'description': _("Description"),
-        'owner': _("Owner"),
-        'is_hidden': _("Is Hidden"),
-        'filter_select_enabled': _("Enable Filter Select"),
-        'default_endpoint': _("Default Endpoint"),
-        'offset': _("Time Offset"),
-        'cache_timeout': _("Cache Timeout"),
+        'slices': _('Associated Slices'),
+        'datasource_link': _('Data Source'),
+        'cluster': _('Cluster'),
+        'description': _('Description'),
+        'owner': _('Owner'),
+        'is_hidden': _('Is Hidden'),
+        'filter_select_enabled': _('Enable Filter Select'),
+        'default_endpoint': _('Default Endpoint'),
+        'offset': _('Time Offset'),
+        'cache_timeout': _('Cache Timeout'),
     }
 
     def pre_add(self, datasource):
@@ -263,18 +263,18 @@ class DruidDatasourceModelView(DatasourceModelView, DeleteMixin):  # noqa
 
 appbuilder.add_view(
     DruidDatasourceModelView,
-    "Druid Datasources",
-    label=__("Druid Datasources"),
-    category="Sources",
-    category_label=__("Sources"),
-    icon="fa-cube")
+    'Druid Datasources',
+    label=__('Druid Datasources'),
+    category='Sources',
+    category_label=__('Sources'),
+    icon='fa-cube')
 
 
 class Druid(BaseSupersetView):
     """The base views for Superset!"""
 
     @has_access
-    @expose("/refresh_datasources/")
+    @expose('/refresh_datasources/')
     def refresh_datasources(self, refreshAll=True):
         """endpoint that refreshes druid datasources metadata"""
         session = db.session()
@@ -287,19 +287,19 @@ class Druid(BaseSupersetView):
                 flash(
                     "Error while processing cluster '{}'\n{}".format(
                         cluster_name, utils.error_msg_from_exception(e)),
-                    "danger")
+                    'danger')
                 logging.exception(e)
                 return redirect('/druidclustermodelview/list/')
             cluster.metadata_last_refreshed = datetime.now()
             flash(
-                "Refreshed metadata from cluster "
-                "[" + cluster.cluster_name + "]",
+                'Refreshed metadata from cluster '
+                '[' + cluster.cluster_name + ']',
                 'info')
         session.commit()
-        return redirect("/druiddatasourcemodelview/list/")
+        return redirect('/druiddatasourcemodelview/list/')
 
     @has_access
-    @expose("/scan_new_datasources/")
+    @expose('/scan_new_datasources/')
     def scan_new_datasources(self):
         """
         Calling this endpoint will cause a scan for new
@@ -311,21 +311,21 @@ class Druid(BaseSupersetView):
 appbuilder.add_view_no_menu(Druid)
 
 appbuilder.add_link(
-    "Scan New Datasources",
-    label=__("Scan New Datasources"),
+    'Scan New Datasources',
+    label=__('Scan New Datasources'),
     href='/druid/scan_new_datasources/',
     category='Sources',
-    category_label=__("Sources"),
+    category_label=__('Sources'),
     category_icon='fa-database',
-    icon="fa-refresh")
+    icon='fa-refresh')
 appbuilder.add_link(
-    "Refresh Druid Metadata",
-    label=__("Refresh Druid Metadata"),
+    'Refresh Druid Metadata',
+    label=__('Refresh Druid Metadata'),
     href='/druid/refresh_datasources/',
     category='Sources',
-    category_label=__("Sources"),
+    category_label=__('Sources'),
     category_icon='fa-database',
-    icon="fa-cog")
+    icon='fa-cog')
 
 
-appbuilder.add_separator("Sources", )
+appbuilder.add_separator('Sources', )
diff --git a/superset/connectors/sqla/models.py b/superset/connectors/sqla/models.py
index 8c70db3..d7081d2 100644
--- a/superset/connectors/sqla/models.py
+++ b/superset/connectors/sqla/models.py
@@ -138,7 +138,7 @@ class SqlMetric(Model, BaseMetric):
     @property
     def perm(self):
         return (
-            "{parent_name}.[{obj.metric_name}](id:{obj.id})"
+            '{parent_name}.[{obj.metric_name}](id:{obj.id})'
         ).format(obj=self,
                  parent_name=self.table.full_name) if self.table else None
 
@@ -155,7 +155,7 @@ class SqlaTable(Model, BaseDatasource):
 
     """An ORM object for SqlAlchemy table references"""
 
-    type = "table"
+    type = 'table'
     query_language = 'sql'
     metric_class = SqlMetric
     column_class = TableColumn
@@ -177,7 +177,7 @@ class SqlaTable(Model, BaseDatasource):
     schema = Column(String(255))
     sql = Column(Text)
 
-    baselink = "tablemodelview"
+    baselink = 'tablemodelview'
     export_fields = (
         'table_name', 'main_dttm_col', 'description', 'default_endpoint',
         'database_id', 'offset', 'cache_timeout', 'schema',
@@ -212,14 +212,14 @@ class SqlaTable(Model, BaseDatasource):
 
     def get_perm(self):
         return (
-            "[{obj.database}].[{obj.table_name}]"
-            "(id:{obj.id})").format(obj=self)
+            '[{obj.database}].[{obj.table_name}]'
+            '(id:{obj.id})').format(obj=self)
 
     @property
     def name(self):
         if not self.schema:
             return self.table_name
-        return "{}.{}".format(self.schema, self.table_name)
+        return '{}.{}'.format(self.schema, self.table_name)
 
     @property
     def full_name(self):
@@ -251,18 +251,18 @@ class SqlaTable(Model, BaseDatasource):
         return df.to_html(
             index=False,
             classes=(
-                "dataframe table table-striped table-bordered "
-                "table-condensed"))
+                'dataframe table table-striped table-bordered '
+                'table-condensed'))
 
     @property
     def sql_url(self):
-        return self.database.sql_url + "?table_name=" + str(self.table_name)
+        return self.database.sql_url + '?table_name=' + str(self.table_name)
 
     @property
     def time_column_grains(self):
         return {
-            "time_columns": self.dttm_cols,
-            "time_grains": [grain.name for grain in self.database.grains()],
+            'time_columns': self.dttm_cols,
+            'time_grains': [grain.name for grain in self.database.grains()],
         }
 
     def get_col(self, col_name):
@@ -304,9 +304,9 @@ class SqlaTable(Model, BaseDatasource):
             qry = qry.where(tp.process_template(self.fetch_values_predicate))
 
         engine = self.database.get_sqla_engine()
-        sql = "{}".format(
+        sql = '{}'.format(
             qry.compile(
-                engine, compile_kwargs={"literal_binds": True}, ),
+                engine, compile_kwargs={'literal_binds': True}, ),
         )
 
         df = pd.read_sql_query(sql=sql, con=engine)
@@ -322,7 +322,7 @@ class SqlaTable(Model, BaseDatasource):
         sql = str(
             qry.compile(
                 engine,
-                compile_kwargs={"literal_binds": True},
+                compile_kwargs={'literal_binds': True},
             ),
         )
         logging.info(sql)
@@ -389,10 +389,10 @@ class SqlaTable(Model, BaseDatasource):
 
         if not granularity and is_timeseries:
             raise Exception(_(
-                "Datetime column not provided as part table configuration "
-                "and is required by this type of chart"))
+                'Datetime column not provided as part table configuration '
+                'and is required by this type of chart'))
         if not groupby and not metrics and not columns:
-            raise Exception(_("Empty query?"))
+            raise Exception(_('Empty query?'))
         for m in metrics:
             if m not in metrics_dict:
                 raise Exception(_("Metric '{}' is not valid".format(m)))
@@ -400,7 +400,7 @@ class SqlaTable(Model, BaseDatasource):
         if metrics_exprs:
             main_metric_expr = metrics_exprs[0]
         else:
-            main_metric_expr = literal_column("COUNT(*)").label("ccount")
+            main_metric_expr = literal_column('COUNT(*)').label('ccount')
 
         select_exprs = []
         groupby_exprs = []
@@ -465,7 +465,7 @@ class SqlaTable(Model, BaseDatasource):
                         # For backwards compatibility and edge cases
                         # where a column data type might have changed
                         if isinstance(v, basestring):
-                            v = v.strip("'").strip('"')
+                            v = v.strip(""").strip(""")
                             if col_obj.is_num:
                                 v = utils.string_to_num(v)
 
@@ -600,9 +600,9 @@ class SqlaTable(Model, BaseDatasource):
             try:
                 datatype = col.type.compile(dialect=db_dialect).upper()
             except Exception as e:
-                datatype = "UNKNOWN"
+                datatype = 'UNKNOWN'
                 logging.error(
-                    "Unrecognized data type in {}.{}".format(table, col.name))
+                    'Unrecognized data type in {}.{}'.format(table, col.name))
                 logging.exception(e)
             dbcol = dbcols.get(col.name, None)
             if not dbcol:
@@ -622,35 +622,35 @@ class SqlaTable(Model, BaseDatasource):
                     metric_name='sum__' + dbcol.column_name,
                     verbose_name='sum__' + dbcol.column_name,
                     metric_type='sum',
-                    expression="SUM({})".format(quoted),
+                    expression='SUM({})'.format(quoted),
                 ))
             if dbcol.avg:
                 metrics.append(M(
                     metric_name='avg__' + dbcol.column_name,
                     verbose_name='avg__' + dbcol.column_name,
                     metric_type='avg',
-                    expression="AVG({})".format(quoted),
+                    expression='AVG({})'.format(quoted),
                 ))
             if dbcol.max:
                 metrics.append(M(
                     metric_name='max__' + dbcol.column_name,
                     verbose_name='max__' + dbcol.column_name,
                     metric_type='max',
-                    expression="MAX({})".format(quoted),
+                    expression='MAX({})'.format(quoted),
                 ))
             if dbcol.min:
                 metrics.append(M(
                     metric_name='min__' + dbcol.column_name,
                     verbose_name='min__' + dbcol.column_name,
                     metric_type='min',
-                    expression="MIN({})".format(quoted),
+                    expression='MIN({})'.format(quoted),
                 ))
             if dbcol.count_distinct:
                 metrics.append(M(
                     metric_name='count_distinct__' + dbcol.column_name,
                     verbose_name='count_distinct__' + dbcol.column_name,
                     metric_type='count_distinct',
-                    expression="COUNT(DISTINCT {})".format(quoted),
+                    expression='COUNT(DISTINCT {})'.format(quoted),
                 ))
             dbcol.type = datatype
 
@@ -658,7 +658,7 @@ class SqlaTable(Model, BaseDatasource):
             metric_name='count',
             verbose_name='COUNT(*)',
             metric_type='count',
-            expression="COUNT(*)",
+            expression='COUNT(*)',
         ))
 
         dbmetrics = db.session.query(M).filter(M.table_id == self.id).filter(
diff --git a/superset/connectors/sqla/views.py b/superset/connectors/sqla/views.py
index 586c776..47358fa 100644
--- a/superset/connectors/sqla/views.py
+++ b/superset/connectors/sqla/views.py
@@ -39,54 +39,54 @@ class TableColumnInlineView(CompactCRUDMixin, SupersetModelView):  # noqa
     page_size = 500
     description_columns = {
         'is_dttm': _(
-            "Whether to make this column available as a "
-            "[Time Granularity] option, column has to be DATETIME or "
-            "DATETIME-like"),
+            'Whether to make this column available as a '
+            '[Time Granularity] option, column has to be DATETIME or '
+            'DATETIME-like'),
         'filterable': _(
-            "Whether this column is exposed in the `Filters` section "
-            "of the explore view."),
+            'Whether this column is exposed in the `Filters` section '
+            'of the explore view.'),
         'type': _(
-            "The data type that was inferred by the database. "
-            "It may be necessary to input a type manually for "
-            "expression-defined columns in some cases. In most case "
-            "users should not need to alter this."),
+            'The data type that was inferred by the database. '
+            'It may be necessary to input a type manually for '
+            'expression-defined columns in some cases. In most case '
+            'users should not need to alter this.'),
         'expression': utils.markdown(
-            "a valid SQL expression as supported by the underlying backend. "
-            "Example: `substr(name, 1, 1)`", True),
+            'a valid SQL expression as supported by the underlying backend. '
+            'Example: `substr(name, 1, 1)`', True),
         'python_date_format': utils.markdown(Markup(
-            "The pattern of timestamp format, use "
-            "<a href='https://docs.python.org/2/library/"
-            "datetime.html#strftime-strptime-behavior'>"
-            "python datetime string pattern</a> "
-            "expression. If time is stored in epoch "
-            "format, put `epoch_s` or `epoch_ms`. Leave `Database Expression` "
-            "below empty if timestamp is stored in "
-            "String or Integer(epoch) type"), True),
+            'The pattern of timestamp format, use '
+            '<a href="https://docs.python.org/2/library/'
+            'datetime.html#strftime-strptime-behavior">'
+            'python datetime string pattern</a> '
+            'expression. If time is stored in epoch '
+            'format, put `epoch_s` or `epoch_ms`. Leave `Database Expression` '
+            'below empty if timestamp is stored in '
+            'String or Integer(epoch) type'), True),
         'database_expression': utils.markdown(
-            "The database expression to cast internal datetime "
-            "constants to database date/timestamp type according to the DBAPI. "
-            "The expression should follow the pattern of "
-            "%Y-%m-%d %H:%M:%S, based on different DBAPI. "
-            "The string should be a python string formatter \n"
-            "`Ex: TO_DATE('{}', 'YYYY-MM-DD HH24:MI:SS')` for Oracle"
-            "Superset uses default expression based on DB URI if this "
-            "field is blank.", True),
+            'The database expression to cast internal datetime '
+            'constants to database date/timestamp type according to the DBAPI. '
+            'The expression should follow the pattern of '
+            '%Y-%m-%d %H:%M:%S, based on different DBAPI. '
+            'The string should be a python string formatter \n'
+            "`Ex: TO_DATE('{}', 'YYYY-MM-DD HH24:MI:SS')` for Oracle "
+            'Superset uses default expression based on DB URI if this '
+            'field is blank.', True),
     }
     label_columns = {
-        'column_name': _("Column"),
-        'verbose_name': _("Verbose Name"),
-        'description': _("Description"),
-        'groupby': _("Groupable"),
-        'filterable': _("Filterable"),
-        'table': _("Table"),
-        'count_distinct': _("Count Distinct"),
-        'sum': _("Sum"),
-        'min': _("Min"),
-        'max': _("Max"),
-        'expression': _("Expression"),
-        'is_dttm': _("Is temporal"),
-        'python_date_format': _("Datetime Format"),
-        'database_expression': _("Database Expression"),
+        'column_name': _('Column'),
+        'verbose_name': _('Verbose Name'),
+        'description': _('Description'),
+        'groupby': _('Groupable'),
+        'filterable': _('Filterable'),
+        'table': _('Table'),
+        'count_distinct': _('Count Distinct'),
+        'sum': _('Sum'),
+        'min': _('Min'),
+        'max': _('Max'),
+        'expression': _('Expression'),
+        'is_dttm': _('Is temporal'),
+        'python_date_format': _('Datetime Format'),
+        'database_expression': _('Database Expression'),
         'type': _('Type'),
     }
 
@@ -108,30 +108,30 @@ class SqlMetricInlineView(CompactCRUDMixin, SupersetModelView):  # noqa
         'expression', 'table', 'd3format', 'is_restricted', 'warning_text']
     description_columns = {
         'expression': utils.markdown(
-            "a valid SQL expression as supported by the underlying backend. "
-            "Example: `count(DISTINCT userid)`", True),
-        'is_restricted': _("Whether the access to this metric is restricted "
-                           "to certain roles. Only roles with the permission "
+            'a valid SQL expression as supported by the underlying backend. '
+            'Example: `count(DISTINCT userid)`', True),
+        'is_restricted': _('Whether the access to this metric is restricted '
+                           'to certain roles. Only roles with the permission '
                            "'metric access on XXX (the name of this metric)' "
-                           "are allowed to access this metric"),
+                           'are allowed to access this metric'),
         'd3format': utils.markdown(
-            "d3 formatting string as defined [here]"
-            "(https://github.com/d3/d3-format/blob/master/README.md#format). "
-            "For instance, this default formatting applies in the Table "
-            "visualization and allow for different metric to use different "
-            "formats", True,
+            'd3 formatting string as defined [here]'
+            '(https://github.com/d3/d3-format/blob/master/README.md#format). '
+            'For instance, this default formatting applies in the Table '
+            'visualization and allow for different metric to use different '
+            'formats', True,
         ),
     }
     add_columns = edit_columns
     page_size = 500
     label_columns = {
-        'metric_name': _("Metric"),
-        'description': _("Description"),
-        'verbose_name': _("Verbose Name"),
-        'metric_type': _("Type"),
-        'expression': _("SQL Expression"),
-        'table': _("Table"),
-        'd3format': _("D3 Format"),
+        'metric_name': _('Metric'),
+        'description': _('Description'),
+        'verbose_name': _('Verbose Name'),
+        'metric_type': _('Type'),
+        'expression': _('SQL Expression'),
+        'table': _('Table'),
+        'd3format': _('D3 Format'),
         'is_restricted': _('Is Restricted'),
         'warning_text': _('Warning Message'),
     }
@@ -174,56 +174,56 @@ class TableModelView(DatasourceModelView, DeleteMixin):  # noqa
     )
     description_columns = {
         'slices': _(
-            "The list of slices associated with this table. By "
-            "altering this datasource, you may change how these associated "
-            "slices behave. "
-            "Also note that slices need to point to a datasource, so "
-            "this form will fail at saving if removing slices from a "
-            "datasource. If you want to change the datasource for a slice, "
+            'The list of slices associated with this table. By '
+            'altering this datasource, you may change how these associated '
+            'slices behave. '
+            'Also note that slices need to point to a datasource, so '
+            'this form will fail at saving if removing slices from a '
+            'datasource. If you want to change the datasource for a slice, '
             "overwrite the slice from the 'explore view'"),
-        'offset': _("Timezone offset (in hours) for this datasource"),
+        'offset': _('Timezone offset (in hours) for this datasource'),
         'table_name': _(
-            "Name of the table that exists in the source database"),
+            'Name of the table that exists in the source database'),
         'schema': _(
-            "Schema, as used only in some databases like Postgres, Redshift "
-            "and DB2"),
+            'Schema, as used only in some databases like Postgres, Redshift '
+            'and DB2'),
         'description': Markup(
-            "Supports <a href='https://daringfireball.net/projects/markdown/'>"
-            "markdown</a>"),
+            'Supports <a href="https://daringfireball.net/projects/markdown/">'
+            'markdown</a>'),
         'sql': _(
-            "This fields acts a Superset view, meaning that Superset will "
-            "run a query against this string as a subquery.",
+            'This fields acts a Superset view, meaning that Superset will '
+            'run a query against this string as a subquery.',
         ),
         'fetch_values_predicate': _(
-            "Predicate applied when fetching distinct value to "
-            "populate the filter control component. Supports "
-            "jinja template syntax. Applies only when "
-            "`Enable Filter Select` is on.",
+            'Predicate applied when fetching distinct value to '
+            'populate the filter control component. Supports '
+            'jinja template syntax. Applies only when '
+            '`Enable Filter Select` is on.',
         ),
         'default_endpoint': _(
-            "Redirects to this endpoint when clicking on the table "
-            "from the table list"),
+            'Redirects to this endpoint when clicking on the table '
+            'from the table list'),
         'filter_select_enabled': _(
             "Whether to populate the filter's dropdown in the explore "
             "view's filter section with a list of distinct values fetched "
-            "from the backend on the fly"),
+            'from the backend on the fly'),
     }
     base_filters = [['id', DatasourceFilter, lambda: []]]
     label_columns = {
-        'slices': _("Associated Slices"),
-        'link': _("Table"),
-        'changed_by_': _("Changed By"),
-        'database': _("Database"),
-        'changed_on_': _("Last Changed"),
-        'filter_select_enabled': _("Enable Filter Select"),
-        'schema': _("Schema"),
+        'slices': _('Associated Slices'),
+        'link': _('Table'),
+        'changed_by_': _('Changed By'),
+        'database': _('Database'),
+        'changed_on_': _('Last Changed'),
+        'filter_select_enabled': _('Enable Filter Select'),
+        'schema': _('Schema'),
         'default_endpoint': _('Default Endpoint'),
-        'offset': _("Offset"),
-        'cache_timeout': _("Cache Timeout"),
-        'table_name': _("Table Name"),
+        'offset': _('Offset'),
+        'cache_timeout': _('Cache Timeout'),
+        'table_name': _('Table Name'),
         'fetch_values_predicate': _('Fetch Values Predicate'),
-        'owner': _("Owner"),
-        'main_dttm_col': _("Main Datetime Column"),
+        'owner': _('Owner'),
+        'main_dttm_col': _('Main Datetime Column'),
         'description': _('Description'),
     }
 
@@ -240,10 +240,10 @@ class TableModelView(DatasourceModelView, DeleteMixin):  # noqa
         # Fail before adding if the table can't be found
         if not table.database.has_table(table):
             raise Exception(_(
-                "Table [{}] could not be found, "
-                "please double check your "
-                "database connection, schema, and "
-                "table name").format(table.name))
+                'Table [{}] could not be found, '
+                'please double check your '
+                'database connection, schema, and '
+                'table name').format(table.name))
 
     def post_add(self, table, flash_message=True):
         table.fetch_metadata()
@@ -253,10 +253,10 @@ class TableModelView(DatasourceModelView, DeleteMixin):  # noqa
 
         if flash_message:
             flash(_(
-                "The table was created. "
-                "As part of this two phase configuration "
-                "process, you should now click the edit button by "
-                "the new table to configure it."), "info")
+                'The table was created. '
+                'As part of this two phase configuration '
+                'process, you should now click the edit button by '
+                'the new table to configure it.'), 'info')
 
     def post_update(self, table):
         self.post_add(table, flash_message=False)
@@ -274,26 +274,26 @@ class TableModelView(DatasourceModelView, DeleteMixin):  # noqa
         return redirect('/superset/explore/table/{}/'.format(pk))
 
     @action(
-        "refresh",
-        __("Refresh Metadata"),
-        __("Refresh column metadata"),
-        "fa-refresh")
+        'refresh',
+        __('Refresh Metadata'),
+        __('Refresh column metadata'),
+        'fa-refresh')
     def refresh(self, tables):
         for t in tables:
             t.fetch_metadata()
         msg = _(
-            "Metadata refreshed for the following table(s): %(tables)s",
-            tables=", ".join([t.table_name for t in tables]))
+            'Metadata refreshed for the following table(s): %(tables)s',
+            tables=', '.join([t.table_name for t in tables]))
         flash(msg, 'info')
         return redirect('/tablemodelview/list/')
 
 
 appbuilder.add_view(
     TableModelView,
-    "Tables",
-    label=__("Tables"),
-    category="Sources",
-    category_label=__("Sources"),
+    'Tables',
+    label=__('Tables'),
+    category='Sources',
+    category_label=__('Sources'),
     icon='fa-table',)
 
-appbuilder.add_separator("Sources")
+appbuilder.add_separator('Sources')
diff --git a/superset/db_engine_specs.py b/superset/db_engine_specs.py
index 562f359..4b66fa1 100644
--- a/superset/db_engine_specs.py
+++ b/superset/db_engine_specs.py
@@ -106,7 +106,7 @@ class BaseEngineSpec(object):
             all_result_sets += [
                 '{}.{}'.format(schema, t) for t in result_sets[schema]]
         if all_result_sets:
-            result_sets[""] = all_result_sets
+            result_sets[''] = all_result_sets
         return result_sets
 
     @classmethod
@@ -139,7 +139,7 @@ class BaseEngineSpec(object):
         For those it's probably better to not alter the database
         component of the URI with the schema name, it won't work.
 
-        Some database drivers like presto accept "{catalog}/{schema}" in
+        Some database drivers like presto accept '{catalog}/{schema}' in
         the database component of the URL, that can be handled here.
         """
         return uri
@@ -211,15 +211,15 @@ class PostgresEngineSpec(BaseEngineSpec):
     engine = 'postgresql'
 
     time_grains = (
-        Grain("Time Column", _('Time Column'), "{col}"),
-        Grain("second", _('second'), "DATE_TRUNC('second', \"{col}\")"),
-        Grain("minute", _('minute'), "DATE_TRUNC('minute', \"{col}\")"),
-        Grain("hour", _('hour'), "DATE_TRUNC('hour', \"{col}\")"),
-        Grain("day", _('day'), "DATE_TRUNC('day', \"{col}\")"),
-        Grain("week", _('week'), "DATE_TRUNC('week', \"{col}\")"),
-        Grain("month", _('month'), "DATE_TRUNC('month', \"{col}\")"),
-        Grain("quarter", _('quarter'), "DATE_TRUNC('quarter', \"{col}\")"),
-        Grain("year", _('year'), "DATE_TRUNC('year', \"{col}\")"),
+        Grain('Time Column', _('Time Column'), '{col}'),
+        Grain('second', _('second'), "DATE_TRUNC('second', '{col}')"),
+        Grain('minute', _('minute'), "DATE_TRUNC('minute', '{col}')"),
+        Grain('hour', _('hour'), "DATE_TRUNC('hour', '{col}')"),
+        Grain('day', _('day'), "DATE_TRUNC('day', '{col}')"),
+        Grain('week', _('week'), "DATE_TRUNC('week', '{col}')"),
+        Grain('month', _('month'), "DATE_TRUNC('month', '{col}')"),
+        Grain('quarter', _('quarter'), "DATE_TRUNC('quarter', '{col}')"),
+        Grain('year', _('year'), "DATE_TRUNC('year', '{col}')"),
     )
 
     @classmethod
@@ -295,9 +295,9 @@ class SqliteEngineSpec(BaseEngineSpec):
     time_grains = (
         Grain('Time Column', _('Time Column'), '{col}'),
         Grain('day', _('day'), 'DATE({col})'),
-        Grain("week", _('week'),
+        Grain('week', _('week'),
               "DATE({col}, -strftime('%w', {col}) || ' days')"),
-        Grain("month", _('month'),
+        Grain('month', _('month'),
               "DATE({col}, -strftime('%d', {col}) || ' days', '+1 day')"),
     )
 
@@ -321,7 +321,7 @@ class SqliteEngineSpec(BaseEngineSpec):
         all_result_sets += [
             '{}.{}'.format(schema, t) for t in result_sets[schema]]
         if all_result_sets:
-            result_sets[""] = all_result_sets
+            result_sets[''] = all_result_sets
         return result_sets
 
     @classmethod
@@ -342,25 +342,25 @@ class MySQLEngineSpec(BaseEngineSpec):
     cursor_execute_kwargs = {'args': {}}
     time_grains = (
         Grain('Time Column', _('Time Column'), '{col}'),
-        Grain("second", _('second'), "DATE_ADD(DATE({col}), "
-              "INTERVAL (HOUR({col})*60*60 + MINUTE({col})*60"
-              " + SECOND({col})) SECOND)"),
-        Grain("minute", _('minute'), "DATE_ADD(DATE({col}), "
-              "INTERVAL (HOUR({col})*60 + MINUTE({col})) MINUTE)"),
-        Grain("hour", _('hour'), "DATE_ADD(DATE({col}), "
-              "INTERVAL HOUR({col}) HOUR)"),
+        Grain('second', _('second'), 'DATE_ADD(DATE({col}), '
+              'INTERVAL (HOUR({col})*60*60 + MINUTE({col})*60'
+              ' + SECOND({col})) SECOND)'),
+        Grain('minute', _('minute'), 'DATE_ADD(DATE({col}), '
+              'INTERVAL (HOUR({col})*60 + MINUTE({col})) MINUTE)'),
+        Grain('hour', _('hour'), 'DATE_ADD(DATE({col}), '
+              'INTERVAL HOUR({col}) HOUR)'),
         Grain('day', _('day'), 'DATE({col})'),
-        Grain("week", _('week'), "DATE(DATE_SUB({col}, "
-              "INTERVAL DAYOFWEEK({col}) - 1 DAY))"),
-        Grain("month", _('month'), "DATE(DATE_SUB({col}, "
-              "INTERVAL DAYOFMONTH({col}) - 1 DAY))"),
-        Grain("quarter", _('quarter'), "MAKEDATE(YEAR({col}), 1) "
-              "+ INTERVAL QUARTER({col}) QUARTER - INTERVAL 1 QUARTER"),
-        Grain("year", _('year'), "DATE(DATE_SUB({col}, "
-              "INTERVAL DAYOFYEAR({col}) - 1 DAY))"),
-        Grain("week_start_monday", _('week_start_monday'),
-              "DATE(DATE_SUB({col}, "
-              "INTERVAL DAYOFWEEK(DATE_SUB({col}, INTERVAL 1 DAY)) - 1 DAY))"),
+        Grain('week', _('week'), 'DATE(DATE_SUB({col}, '
+              'INTERVAL DAYOFWEEK({col}) - 1 DAY))'),
+        Grain('month', _('month'), 'DATE(DATE_SUB({col}, '
+              'INTERVAL DAYOFMONTH({col}) - 1 DAY))'),
+        Grain('quarter', _('quarter'), 'MAKEDATE(YEAR({col}), 1) '
+              '+ INTERVAL QUARTER({col}) QUARTER - INTERVAL 1 QUARTER'),
+        Grain('year', _('year'), 'DATE(DATE_SUB({col}, '
+              'INTERVAL DAYOFYEAR({col}) - 1 DAY))'),
+        Grain('week_start_monday', _('week_start_monday'),
+              'DATE(DATE_SUB({col}, '
+              'INTERVAL DAYOFWEEK(DATE_SUB({col}, INTERVAL 1 DAY)) - 1 DAY))'),
     )
 
     @classmethod
@@ -378,7 +378,7 @@ class MySQLEngineSpec(BaseEngineSpec):
 
     @classmethod
     def epoch_to_dttm(cls):
-        return "from_unixtime({col})"
+        return 'from_unixtime({col})'
 
     @classmethod
     def extract_error_message(cls, e):
@@ -412,10 +412,10 @@ class PrestoEngineSpec(BaseEngineSpec):
               "date_trunc('month', CAST({col} AS TIMESTAMP))"),
         Grain('quarter', _('quarter'),
               "date_trunc('quarter', CAST({col} AS TIMESTAMP))"),
-        Grain("week_ending_saturday", _('week_ending_saturday'),
+        Grain('week_ending_saturday', _('week_ending_saturday'),
               "date_add('day', 5, date_trunc('week', date_add('day', 1, "
-              "CAST({col} AS TIMESTAMP))))"),
-        Grain("week_start_sunday", _('week_start_sunday'),
+              'CAST({col} AS TIMESTAMP))))'),
+        Grain('week_start_sunday', _('week_start_sunday'),
               "date_add('day', -1, date_trunc('week', "
               "date_add('day', 1, CAST({col} AS TIMESTAMP))))"),
     )
@@ -439,7 +439,7 @@ class PrestoEngineSpec(BaseEngineSpec):
 
     @classmethod
     def escape_sql(cls, sql):
-        return re.sub(r'%%|%', "%%", sql)
+        return re.sub(r'%%|%', '%%', sql)
 
     @classmethod
     def convert_dttm(cls, target_type, dttm):
@@ -452,7 +452,7 @@ class PrestoEngineSpec(BaseEngineSpec):
 
     @classmethod
     def epoch_to_dttm(cls):
-        return "from_unixtime({col})"
+        return 'from_unixtime({col})'
 
     @classmethod
     @cache_util.memoized_func(
@@ -474,7 +474,7 @@ class PrestoEngineSpec(BaseEngineSpec):
         result_sets = defaultdict(list)
         for unused, row in result_set_df.iterrows():
             result_sets[row['table_schema']].append(row['table_name'])
-            result_sets[""].append('{}.{}'.format(
+            result_sets[''].append('{}.{}'.format(
                 row['table_schema'], row['table_name']))
         return result_sets
 
@@ -486,7 +486,7 @@ class PrestoEngineSpec(BaseEngineSpec):
         cols = indexes[0].get('column_names', [])
         full_table_name = table_name
         if schema_name and '.' not in table_name:
-            full_table_name = "{}.{}".format(schema_name, table_name)
+            full_table_name = '{}.{}'.format(schema_name, table_name)
         pql = cls._partition_query(full_table_name)
         col_name, latest_part = cls.latest_partition(
             table_name, schema_name, database, show_first=True)
@@ -561,7 +561,7 @@ class PrestoEngineSpec(BaseEngineSpec):
         :param filters: a list of filters to apply
         :param filters: dict of field name and filter value combinations
         """
-        limit_clause = "LIMIT {}".format(limit) if limit else ''
+        limit_clause = 'LIMIT {}'.format(limit) if limit else ''
         order_by_clause = ''
         if order_by:
             l = []  # noqa: E741
@@ -610,12 +610,12 @@ class PrestoEngineSpec(BaseEngineSpec):
         indexes = database.get_indexes(table_name, schema)
         if len(indexes[0]['column_names']) < 1:
             raise SupersetTemplateException(
-                "The table should have one partitioned field")
+                'The table should have one partitioned field')
         elif not show_first and len(indexes[0]['column_names']) > 1:
             raise SupersetTemplateException(
-                "The table should have a single partitioned field "
-                "to use this function. You may want to use "
-                "`presto.latest_sub_partition`")
+                'The table should have a single partitioned field '
+                'to use this function. You may want to use '
+                '`presto.latest_sub_partition`')
         part_field = indexes[0]['column_names'][0]
         sql = cls._partition_query(table_name, 1, [(part_field, True)])
         df = database.get_df(sql, schema)
@@ -652,12 +652,12 @@ class PrestoEngineSpec(BaseEngineSpec):
         part_fields = indexes[0]['column_names']
         for k in kwargs.keys():
             if k not in k in part_fields:
-                msg = "Field [{k}] is not part of the portioning key"
+                msg = 'Field [{k}] is not part of the portioning key'
                 raise SupersetTemplateException(msg)
         if len(kwargs.keys()) != len(part_fields) - 1:
             msg = (
-                "A filter needs to be specified for {} out of the "
-                "{} fields."
+                'A filter needs to be specified for {} out of the '
+                '{} fields.'
             ).format(len(part_fields) - 1, len(part_fields))
             raise SupersetTemplateException(msg)
 
@@ -762,9 +762,9 @@ class HiveEngineSpec(PrestoEngineSpec):
                 reduce_progress = int(match.groupdict()['reduce_progress'])
                 stages[stage_number] = (map_progress + reduce_progress) / 2
         logging.info(
-            "Progress detail: {}, "
-            "current job {}, "
-            "total jobs: {}".format(stages, current_job, total_jobs))
+            'Progress detail: {}, '
+            'current job {}, '
+            'total jobs: {}'.format(stages, current_job, total_jobs))
 
         stage_progress = sum(
             stages.values()) / len(stages.values()) if stages else 0
@@ -776,7 +776,7 @@ class HiveEngineSpec(PrestoEngineSpec):
 
     @classmethod
     def get_tracking_url(cls, log_lines):
-        lkp = "Tracking URL = "
+        lkp = 'Tracking URL = '
         for line in log_lines:
             if lkp in line:
                 return line.split(lkp)[1]
@@ -803,7 +803,7 @@ class HiveEngineSpec(PrestoEngineSpec):
             if log:
                 log_lines = log.splitlines()
                 progress = cls.progress(log_lines)
-                logging.info("Progress total: {}".format(progress))
+                logging.info('Progress total: {}'.format(progress))
                 needs_commit = False
                 if progress > query.progress:
                     query.progress = progress
@@ -813,19 +813,19 @@ class HiveEngineSpec(PrestoEngineSpec):
                     if tracking_url:
                         job_id = tracking_url.split('/')[-2]
                         logging.info(
-                            "Found the tracking url: {}".format(tracking_url))
+                            'Found the tracking url: {}'.format(tracking_url))
                         tracking_url = tracking_url_trans(tracking_url)
                         logging.info(
-                            "Transformation applied: {}".format(tracking_url))
+                            'Transformation applied: {}'.format(tracking_url))
                         query.tracking_url = tracking_url
-                        logging.info("Job id: {}".format(job_id))
+                        logging.info('Job id: {}'.format(job_id))
                         needs_commit = True
                 if job_id and len(log_lines) > last_log_line:
                     # Wait for job id before logging things out
                     # this allows for prefixing all log lines and becoming
                     # searchable in something like Kibana
                     for l in log_lines[last_log_line:]:
-                        logging.info("[{}] {}".format(job_id, l))
+                        logging.info('[{}] {}'.format(job_id, l))
                     last_log_line = len(log_lines)
                 if needs_commit:
                     session.commit()
@@ -859,7 +859,7 @@ class HiveEngineSpec(PrestoEngineSpec):
     @classmethod
     def _partition_query(
             cls, table_name, limit=0, order_by=None, filters=None):
-        return "SHOW PARTITIONS {table_name}".format(**locals())
+        return 'SHOW PARTITIONS {table_name}'.format(**locals())
 
     @classmethod
     def modify_url_for_impersonation(cls, url, impersonate_user, username):
@@ -888,9 +888,9 @@ class HiveEngineSpec(PrestoEngineSpec):
         backend_name = url.get_backend_name()
 
         # Must be Hive connection, enable impersonation, and set param auth=LDAP|KERBEROS
-        if (backend_name == "hive" and "auth" in url.query.keys() and
+        if (backend_name == 'hive' and 'auth' in url.query.keys() and
                 impersonate_user is True and username is not None):
-            configuration["hive.server2.proxy.user"] = username
+            configuration['hive.server2.proxy.user'] = username
         return configuration
 
 
@@ -899,27 +899,27 @@ class MssqlEngineSpec(BaseEngineSpec):
     epoch_to_dttm = "dateadd(S, {col}, '1970-01-01')"
 
     time_grains = (
-        Grain("Time Column", _('Time Column'), "{col}"),
-        Grain("second", _('second'), "DATEADD(second, "
+        Grain('Time Column', _('Time Column'), '{col}'),
+        Grain('second', _('second'), 'DATEADD(second, '
               "DATEDIFF(second, '2000-01-01', {col}), '2000-01-01')"),
-        Grain("minute", _('minute'), "DATEADD(minute, "
-              "DATEDIFF(minute, 0, {col}), 0)"),
-        Grain("5 minute", _('5 minute'), "DATEADD(minute, "
-              "DATEDIFF(minute, 0, {col}) / 5 * 5, 0)"),
-        Grain("half hour", _('half hour'), "DATEADD(minute, "
-              "DATEDIFF(minute, 0, {col}) / 30 * 30, 0)"),
-        Grain("hour", _('hour'), "DATEADD(hour, "
-              "DATEDIFF(hour, 0, {col}), 0)"),
-        Grain("day", _('day'), "DATEADD(day, "
-              "DATEDIFF(day, 0, {col}), 0)"),
-        Grain("week", _('week'), "DATEADD(week, "
-              "DATEDIFF(week, 0, {col}), 0)"),
-        Grain("month", _('month'), "DATEADD(month, "
-              "DATEDIFF(month, 0, {col}), 0)"),
-        Grain("quarter", _('quarter'), "DATEADD(quarter, "
-              "DATEDIFF(quarter, 0, {col}), 0)"),
-        Grain("year", _('year'), "DATEADD(year, "
-              "DATEDIFF(year, 0, {col}), 0)"),
+        Grain('minute', _('minute'), 'DATEADD(minute, '
+              'DATEDIFF(minute, 0, {col}), 0)'),
+        Grain('5 minute', _('5 minute'), 'DATEADD(minute, '
+              'DATEDIFF(minute, 0, {col}) / 5 * 5, 0)'),
+        Grain('half hour', _('half hour'), 'DATEADD(minute, '
+              'DATEDIFF(minute, 0, {col}) / 30 * 30, 0)'),
+        Grain('hour', _('hour'), 'DATEADD(hour, '
+              'DATEDIFF(hour, 0, {col}), 0)'),
+        Grain('day', _('day'), 'DATEADD(day, '
+              'DATEDIFF(day, 0, {col}), 0)'),
+        Grain('week', _('week'), 'DATEADD(week, '
+              'DATEDIFF(week, 0, {col}), 0)'),
+        Grain('month', _('month'), 'DATEADD(month, '
+              'DATEDIFF(month, 0, {col}), 0)'),
+        Grain('quarter', _('quarter'), 'DATEADD(quarter, '
+              'DATEDIFF(quarter, 0, {col}), 0)'),
+        Grain('year', _('year'), 'DATEADD(year, '
+              'DATEDIFF(year, 0, {col}), 0)'),
     )
 
     @classmethod
@@ -955,7 +955,7 @@ class OracleEngineSpec(PostgresEngineSpec):
     @classmethod
     def convert_dttm(cls, target_type, dttm):
         return (
-            """TO_TIMESTAMP('{}', 'YYYY-MM-DD"T"HH24:MI:SS.ff6')"""
+            """TO_TIMESTAMP('{}', 'YYYY-MM-DD'T'HH24:MI:SS.ff6')"""
         ).format(dttm.isoformat())
 
 
@@ -982,10 +982,10 @@ class AthenaEngineSpec(BaseEngineSpec):
               "date_trunc('month', CAST({col} AS TIMESTAMP))"),
         Grain('quarter', _('quarter'),
               "date_trunc('quarter', CAST({col} AS TIMESTAMP))"),
-        Grain("week_ending_saturday", _('week_ending_saturday'),
+        Grain('week_ending_saturday', _('week_ending_saturday'),
               "date_add('day', 5, date_trunc('week', date_add('day', 1, "
-              "CAST({col} AS TIMESTAMP))))"),
-        Grain("week_start_sunday", _('week_start_sunday'),
+              'CAST({col} AS TIMESTAMP))))'),
+        Grain('week_start_sunday', _('week_start_sunday'),
               "date_add('day', -1, date_trunc('week', "
               "date_add('day', 1, CAST({col} AS TIMESTAMP))))"),
     )
@@ -1002,7 +1002,7 @@ class AthenaEngineSpec(BaseEngineSpec):
 
     @classmethod
     def epoch_to_dttm(cls):
-        return "from_unixtime({col})"
+        return 'from_unixtime({col})'
 
 
 class ClickHouseEngineSpec(BaseEngineSpec):
@@ -1015,21 +1015,21 @@ class ClickHouseEngineSpec(BaseEngineSpec):
     time_grains = (
         Grain('Time Column', _('Time Column'), '{col}'),
         Grain('minute', _('minute'),
-              "toStartOfMinute(toDateTime({col}))"),
+              'toStartOfMinute(toDateTime({col}))'),
         Grain('5 minute', _('5 minute'),
-              "toDateTime(intDiv(toUInt32(toDateTime({col})), 300)*300)"),
+              'toDateTime(intDiv(toUInt32(toDateTime({col})), 300)*300)'),
         Grain('10 minute', _('10 minute'),
-              "toDateTime(intDiv(toUInt32(toDateTime({col})), 600)*600)"),
+              'toDateTime(intDiv(toUInt32(toDateTime({col})), 600)*600)'),
         Grain('hour', _('hour'),
-              "toStartOfHour(toDateTime({col}))"),
+              'toStartOfHour(toDateTime({col}))'),
         Grain('day', _('day'),
-              "toStartOfDay(toDateTime({col}))"),
+              'toStartOfDay(toDateTime({col}))'),
         Grain('month', _('month'),
-              "toStartOfMonth(toDateTime({col}))"),
+              'toStartOfMonth(toDateTime({col}))'),
         Grain('quarter', _('quarter'),
-              "toStartOfQuarter(toDateTime({col}))"),
+              'toStartOfQuarter(toDateTime({col}))'),
         Grain('year', _('year'),
-              "toStartOfYear(toDateTime({col}))"),
+              'toStartOfYear(toDateTime({col}))'),
     )
 
     @classmethod
@@ -1050,22 +1050,22 @@ class BQEngineSpec(BaseEngineSpec):
     engine = 'bigquery'
 
     time_grains = (
-        Grain("Time Column", _('Time Column'), "{col}"),
-        Grain("second", _('second'), "TIMESTAMP_TRUNC({col}, SECOND)"),
-        Grain("minute", _('minute'), "TIMESTAMP_TRUNC({col}, MINUTE)"),
-        Grain("hour", _('hour'), "TIMESTAMP_TRUNC({col}, HOUR)"),
-        Grain("day", _('day'), "TIMESTAMP_TRUNC({col}, DAY)"),
-        Grain("week", _('week'), "TIMESTAMP_TRUNC({col}, WEEK)"),
-        Grain("month", _('month'), "TIMESTAMP_TRUNC({col}, MONTH)"),
-        Grain("quarter", _('quarter'), "TIMESTAMP_TRUNC({col}, QUARTER)"),
-        Grain("year", _('year'), "TIMESTAMP_TRUNC({col}, YEAR)"),
+        Grain('Time Column', _('Time Column'), '{col}'),
+        Grain('second', _('second'), 'TIMESTAMP_TRUNC({col}, SECOND)'),
+        Grain('minute', _('minute'), 'TIMESTAMP_TRUNC({col}, MINUTE)'),
+        Grain('hour', _('hour'), 'TIMESTAMP_TRUNC({col}, HOUR)'),
+        Grain('day', _('day'), 'TIMESTAMP_TRUNC({col}, DAY)'),
+        Grain('week', _('week'), 'TIMESTAMP_TRUNC({col}, WEEK)'),
+        Grain('month', _('month'), 'TIMESTAMP_TRUNC({col}, MONTH)'),
+        Grain('quarter', _('quarter'), 'TIMESTAMP_TRUNC({col}, QUARTER)'),
+        Grain('year', _('year'), 'TIMESTAMP_TRUNC({col}, YEAR)'),
     )
 
     @classmethod
     def convert_dttm(cls, target_type, dttm):
         tt = target_type.upper()
         if tt == 'DATE':
-            return "'{}'".format(dttm.strftime('%Y-%m-%d'))
+            return "{}'".format(dttm.strftime('%Y-%m-%d'))
         return "'{}'".format(dttm.strftime('%Y-%m-%d %H:%M:%S'))
 
 
@@ -1075,21 +1075,21 @@ class ImpalaEngineSpec(BaseEngineSpec):
     engine = 'impala'
 
     time_grains = (
-        Grain("Time Column", _('Time Column'), "{col}"),
-        Grain("minute", _('minute'), "TRUNC({col}, 'MI')"),
-        Grain("hour", _('hour'), "TRUNC({col}, 'HH')"),
-        Grain("day", _('day'), "TRUNC({col}, 'DD')"),
-        Grain("week", _('week'), "TRUNC({col}, 'WW')"),
-        Grain("month", _('month'), "TRUNC({col}, 'MONTH')"),
-        Grain("quarter", _('quarter'), "TRUNC({col}, 'Q')"),
-        Grain("year", _('year'), "TRUNC({col}, 'YYYY')"),
+        Grain('Time Column', _('Time Column'), '{col}'),
+        Grain('minute', _('minute'), "TRUNC({col}, 'MI')"),
+        Grain('hour', _('hour'), "TRUNC({col}, 'HH')"),
+        Grain('day', _('day'), "TRUNC({col}, 'DD')"),
+        Grain('week', _('week'), "TRUNC({col}, 'WW')"),
+        Grain('month', _('month'), "TRUNC({col}, 'MONTH')"),
+        Grain('quarter', _('quarter'), "TRUNC({col}, 'Q')"),
+        Grain('year', _('year'), "TRUNC({col}, 'YYYY')"),
     )
 
     @classmethod
     def convert_dttm(cls, target_type, dttm):
         tt = target_type.upper()
         if tt == 'DATE':
-            return "'{}'".format(dttm.strftime('%Y-%m-%d'))
+            return "{}'".format(dttm.strftime('%Y-%m-%d'))
         return "'{}'".format(dttm.strftime('%Y-%m-%d %H:%M:%S'))
 
 
diff --git a/superset/db_engines/hive.py b/superset/db_engines/hive.py
index 635a73b..ae3c1ea 100644
--- a/superset/db_engines/hive.py
+++ b/superset/db_engines/hive.py
@@ -22,7 +22,7 @@ def fetch_logs(self, max_rows=1024,
     except (ttypes.TApplicationException,
             Thrift.TApplicationException):
         if self._state == self._STATE_NONE:
-            raise hive.ProgrammingError("No query yet")
+            raise hive.ProgrammingError('No query yet')
         logs = []
         while True:
             req = ttypes.TFetchResultsReq(
diff --git a/superset/db_engines/presto.py b/superset/db_engines/presto.py
index 57d0460..eb32464 100644
--- a/superset/db_engines/presto.py
+++ b/superset/db_engines/presto.py
@@ -4,17 +4,17 @@ from pyhive import presto
 # TODO(bogdan): Remove this when new pyhive release will be available.
 def cancel(self):
     if self._state == self._STATE_NONE:
-        raise presto.ProgrammingError("No query yet")
+        raise presto.ProgrammingError('No query yet')
     if self._nextUri is None:
         assert self._state == self._STATE_FINISHED, \
-            "Should be finished if nextUri is None"
+            'Should be finished if nextUri is None'
         return
 
     response = presto.requests.delete(self._nextUri)
 
     # pylint: disable=no-member
     if response.status_code != presto.requests.codes.no_content:
-        fmt = "Unexpected status code after cancel {}\n{}"
+        fmt = 'Unexpected status code after cancel {}\n{}'
         raise presto.OperationalError(
             fmt.format(response.status_code, response.content))
     self._state = self._STATE_FINISHED
diff --git a/superset/legacy.py b/superset/legacy.py
index 7585c75..b89b84f 100644
--- a/superset/legacy.py
+++ b/superset/legacy.py
@@ -16,7 +16,7 @@ def cast_filter_data(form_data):
     flts = []
     having_flts = []
     fd = form_data
-    filter_pattern = re.compile(r'''((?:[^,"']|"[^"]*"|'[^']*')+)''')
+    filter_pattern = re.compile(r"""((?:[^,"']|"[^"]*"|'[^']*')+)""")
     for i in range(0, 10):
         for prefix in ['flt', 'having']:
             col_str = '{}_col_{}'.format(prefix, i)
diff --git a/superset/models/core.py b/superset/models/core.py
index 130f63e..d2989d5 100644
--- a/superset/models/core.py
+++ b/superset/models/core.py
@@ -43,7 +43,7 @@ config = app.config
 stats_logger = config.get('STATS_LOGGER')
 metadata = Model.metadata  # pylint: disable=no-member
 
-PASSWORD_MASK = "X" * 10
+PASSWORD_MASK = 'X' * 10
 
 def set_related_perm(mapper, connection, target):  # noqa
     src_class = target.cls_model
@@ -209,19 +209,19 @@ class Slice(Model, AuditMixinNullable, ImportMixin):
     def slice_url(self):
         """Defines the url to access the slice"""
         return (
-            "/superset/explore/{obj.datasource_type}/"
-            "{obj.datasource_id}/?form_data={params}".format(
+            '/superset/explore/{obj.datasource_type}/'
+            '{obj.datasource_id}/?form_data={params}'.format(
                 obj=self, params=parse.quote(json.dumps(self.form_data))))
 
     @property
     def slice_id_url(self):
         return (
-            "/superset/{slc.datasource_type}/{slc.datasource_id}/{slc.id}/"
+            '/superset/{slc.datasource_type}/{slc.datasource_id}/{slc.id}/'
         ).format(slc=self)
 
     @property
     def edit_url(self):
-        return "/slicemodelview/edit/{}".format(self.id)
+        return '/slicemodelview/edit/{}'.format(self.id)
 
     @property
     def slice_link(self):
@@ -238,9 +238,9 @@ class Slice(Model, AuditMixinNullable, ImportMixin):
         """
         slice_params = json.loads(self.params)
         slice_params['slice_id'] = self.id
-        slice_params['json'] = "false"
+        slice_params['json'] = 'false'
         slice_params['slice_name'] = self.slice_name
-        slice_params['viz_type'] = self.viz_type if self.viz_type else "table"
+        slice_params['viz_type'] = self.viz_type if self.viz_type else 'table'
 
         return viz_types[slice_params.get('viz_type')](
             self.datasource,
@@ -327,8 +327,8 @@ class Dashboard(Model, AuditMixinNullable, ImportMixin):
     @property
     def table_names(self):
         # pylint: disable=no-member
-        return ", ".join(
-            {"{}".format(s.datasource.full_name) for s in self.slices})
+        return ', '.join(
+            {'{}'.format(s.datasource.full_name) for s in self.slices})
 
     @property
     def url(self):
@@ -338,9 +338,9 @@ class Dashboard(Model, AuditMixinNullable, ImportMixin):
             default_filters = json_metadata.get('default_filters')
             if default_filters:
                 filters = parse.quote(default_filters.encode('utf8'))
-                return "/superset/dashboard/{}/?preselect_filters={}".format(
+                return '/superset/dashboard/{}/?preselect_filters={}'.format(
                     self.slug or self.id, filters)
-        return "/superset/dashboard/{}/".format(self.slug or self.id)
+        return '/superset/dashboard/{}/'.format(self.slug or self.id)
 
     @property
     def datasources(self):
@@ -538,7 +538,7 @@ class Database(Model, AuditMixinNullable):
     """An ORM object that stores Database related information"""
 
     __tablename__ = 'dbs'
-    type = "table"
+    type = 'table'
 
     id = Column(Integer, primary_key=True)
     verbose_name = Column(String(250), unique=True)
@@ -633,7 +633,7 @@ class Database(Model, AuditMixinNullable):
             effective_username)
 
         masked_url = self.get_password_masked_url(url)
-        logging.info("Database.get_sqla_engine(). Masked URL: {0}".format(masked_url))
+        logging.info('Database.get_sqla_engine(). Masked URL: {0}'.format(masked_url))
 
         params = extra.get('engine_params', {})
         if nullpool:
@@ -647,7 +647,7 @@ class Database(Model, AuditMixinNullable):
                 self.impersonate_user,
                 effective_username))
         if configuration:
-            params["connect_args"] = {"configuration": configuration}
+            params['connect_args'] = {'configuration': configuration}
 
         return create_engine(url, **params)
 
@@ -676,7 +676,7 @@ class Database(Model, AuditMixinNullable):
 
     def compile_sqla_query(self, qry, schema=None):
         eng = self.get_sqla_engine(schema=schema)
-        compiled = qry.compile(eng, compile_kwargs={"literal_binds": True})
+        compiled = qry.compile(eng, compile_kwargs={'literal_binds': True})
         return '{}'.format(compiled)
 
     def select_star(
@@ -709,7 +709,7 @@ class Database(Model, AuditMixinNullable):
         if not schema:
             tables_dict = self.db_engine_spec.fetch_result_sets(
                 self, 'table', force=force)
-            return tables_dict.get("", [])
+            return tables_dict.get('', [])
         return sorted(
             self.db_engine_spec.get_table_names(schema, self.inspector))
 
@@ -717,7 +717,7 @@ class Database(Model, AuditMixinNullable):
         if not schema:
             views_dict = self.db_engine_spec.fetch_result_sets(
                 self, 'view', force=force)
-            return views_dict.get("", [])
+            return views_dict.get('', [])
         views = []
         try:
             views = self.inspector.get_view_names(schema)
@@ -796,7 +796,7 @@ class Database(Model, AuditMixinNullable):
 
     def get_perm(self):
         return (
-            "[{obj.database_name}].(id:{obj.id})").format(obj=self)
+            '[{obj.database_name}].(id:{obj.id})').format(obj=self)
 
     def has_table(self, table):
         engine = self.get_sqla_engine()
@@ -851,7 +851,7 @@ class Log(Model):
             except (ValueError, TypeError):
                 slice_id = 0
 
-            params = ""
+            params = ''
             try:
                 params = json.dumps(d)
             except Exception:
@@ -948,6 +948,6 @@ class DatasourceAccessRequest(Model, AuditMixinNullable):
             )
             href = '<a href="{}">Extend {} Role</a>'.format(url, r.name)
             if r.name in self.ROLES_BLACKLIST:
-                href = "{} Role".format(r.name)
+                href = '{} Role'.format(r.name)
             action_list = action_list + '<li>' + href + '</li>'
         return '<ul>' + action_list + '</ul>'
diff --git a/superset/models/helpers.py b/superset/models/helpers.py
index f179dbe..d4ae9f4 100644
--- a/superset/models/helpers.py
+++ b/superset/models/helpers.py
@@ -39,8 +39,8 @@ class ImportMixin(object):
     @property
     def params_dict(self):
         if self.params:
-            params = re.sub(",[ \t\r\n]+}", "}", self.params)
-            params = re.sub(",[ \t\r\n]+\]", "]", params)
+            params = re.sub(',[ \t\r\n]+}', '}', self.params)
+            params = re.sub(',[ \t\r\n]+\]', ']', params)
             return json.loads(params)
         else:
             return {}
diff --git a/superset/models/sql_lab.py b/superset/models/sql_lab.py
index b4fc8cc..44b692b 100644
--- a/superset/models/sql_lab.py
+++ b/superset/models/sql_lab.py
@@ -122,7 +122,7 @@ class Query(Model):
         tab = (self.tab_name.replace(' ', '_').lower()
                if self.tab_name else 'notab')
         tab = re.sub(r'\W+', '', tab)
-        return "sqllab_{tab}_{ts}".format(**locals())
+        return 'sqllab_{tab}_{ts}'.format(**locals())
 
 
 class SavedQuery(Model, AuditMixinNullable):
diff --git a/superset/security.py b/superset/security.py
index ebb6246..6c7d768 100644
--- a/superset/security.py
+++ b/superset/security.py
@@ -86,15 +86,15 @@ def is_user_defined_permission(perm):
 
 
 def get_or_create_main_db():
-    logging.info("Creating database reference")
+    logging.info('Creating database reference')
     dbobj = (
         db.session.query(models.Database)
         .filter_by(database_name='main')
         .first()
     )
     if not dbobj:
-        dbobj = models.Database(database_name="main")
-    dbobj.set_sqlalchemy_uri(conf.get("SQLALCHEMY_DATABASE_URI"))
+        dbobj = models.Database(database_name='main')
+    dbobj.set_sqlalchemy_uri(conf.get('SQLALCHEMY_DATABASE_URI'))
     dbobj.expose_in_sqllab = True
     dbobj.allow_run_sync = True
     db.session.add(dbobj)
@@ -146,7 +146,7 @@ def is_granter_pvm(pvm):
 
 
 def set_role(role_name, pvm_check):
-    logging.info("Syncing {} perms".format(role_name))
+    logging.info('Syncing {} perms'.format(role_name))
     sesh = sm.get_session()
     pvms = sesh.query(ab_models.PermissionView).all()
     pvms = [p for p in pvms if p.permission and p.view_menu]
@@ -167,7 +167,7 @@ def create_missing_perms():
     """Creates missing perms for datasources, schemas and metrics"""
 
     logging.info(
-        "Fetching a set of all perms to lookup which ones are missing")
+        'Fetching a set of all perms to lookup which ones are missing')
     all_pvs = set()
     for pv in sm.get_session.query(sm.permissionview_model).all():
         if pv.permission and pv.view_menu:
@@ -178,18 +178,18 @@ def create_missing_perms():
         if view_menu and perm and (view_menu, perm) not in all_pvs:
             merge_perm(sm, view_menu, perm)
 
-    logging.info("Creating missing datasource permissions.")
+    logging.info('Creating missing datasource permissions.')
     datasources = ConnectorRegistry.get_all_datasources(db.session)
     for datasource in datasources:
         merge_pv('datasource_access', datasource.get_perm())
         merge_pv('schema_access', datasource.schema_perm)
 
-    logging.info("Creating missing database permissions.")
+    logging.info('Creating missing database permissions.')
     databases = db.session.query(models.Database).all()
     for database in databases:
         merge_pv('database_access', database.perm)
 
-    logging.info("Creating missing metrics permissions")
+    logging.info('Creating missing metrics permissions')
     metrics = []
     for datasource_class in ConnectorRegistry.sources.values():
         metrics += list(db.session.query(datasource_class.metric_class).all())
@@ -201,7 +201,7 @@ def create_missing_perms():
 
 def sync_role_definitions():
     """Inits the Superset application with security roles and such"""
-    logging.info("Syncing role definition")
+    logging.info('Syncing role definition')
 
     get_or_create_main_db()
     create_custom_permissions()
diff --git a/superset/sql_lab.py b/superset/sql_lab.py
index ab0f960..399faee 100644
--- a/superset/sql_lab.py
+++ b/superset/sql_lab.py
@@ -63,13 +63,13 @@ def get_query(query_id, session, retry_count=5):
         except Exception:
             attempt += 1
             logging.error(
-                "Query with id `{}` could not be retrieved".format(query_id))
+                'Query with id `{}` could not be retrieved'.format(query_id))
             stats_logger.incr('error_attempting_orm_query_' + str(attempt))
-            logging.error("Sleeping for a sec before retrying...")
+            logging.error('Sleeping for a sec before retrying...')
             sleep(1)
     if not query:
         stats_logger.incr('error_failed_at_getting_orm_query')
-        raise SqlLabException("Failed at getting query")
+        raise SqlLabException('Failed at getting query')
     return query
 
 
@@ -119,9 +119,9 @@ def execute_sql(
 
     def handle_error(msg):
         """Local method handling error while processing the SQL"""
-        troubleshooting_link = config["TROUBLESHOOTING_LINK"]
-        msg = "Error: {}. You can find common superset errors and their \
-            resolutions at: {}".format(msg, troubleshooting_link) \
+        troubleshooting_link = config['TROUBLESHOOTING_LINK']
+        msg = 'Error: {}. You can find common superset errors and their \
+            resolutions at: {}'.format(msg, troubleshooting_link) \
             if troubleshooting_link else msg
         query.error_message = msg
         query.status = QueryStatus.FAILED
@@ -141,12 +141,12 @@ def execute_sql(
     executed_sql = superset_query.stripped()
     if not superset_query.is_select() and not database.allow_dml:
         return handle_error(
-            "Only `SELECT` statements are allowed against this database")
+            'Only `SELECT` statements are allowed against this database')
     if query.select_as_cta:
         if not superset_query.is_select():
             return handle_error(
-                "Only `SELECT` statements can be used with the CREATE TABLE "
-                "feature.")
+                'Only `SELECT` statements can be used with the CREATE TABLE '
+                'feature.')
             return
         if not query.tmp_table_name:
             start_dttm = datetime.fromtimestamp(query.start_time)
@@ -164,7 +164,7 @@ def execute_sql(
         executed_sql = template_processor.process_template(executed_sql)
     except Exception as e:
         logging.exception(e)
-        msg = "Template rendering failed: " + utils.error_msg_from_exception(e)
+        msg = 'Template rendering failed: ' + utils.error_msg_from_exception(e)
         return handle_error(msg)
 
     query.executed_sql = executed_sql
@@ -182,13 +182,13 @@ def execute_sql(
         )
         conn = engine.raw_connection()
         cursor = conn.cursor()
-        logging.info("Running query: \n{}".format(executed_sql))
+        logging.info('Running query: \n{}'.format(executed_sql))
         logging.info(query.executed_sql)
         cursor.execute(query.executed_sql,
                        **db_engine_spec.cursor_execute_kwargs)
-        logging.info("Handling cursor")
+        logging.info('Handling cursor')
         db_engine_spec.handle_cursor(cursor, query, session)
-        logging.info("Fetching data: {}".format(query.to_dict()))
+        logging.info('Fetching data: {}'.format(query.to_dict()))
         data = db_engine_spec.fetch_data(cursor, query.limit)
     except SoftTimeLimitExceeded as e:
         logging.exception(e)
@@ -196,14 +196,14 @@ def execute_sql(
             conn.close()
         return handle_error(
             "SQL Lab timeout. This environment's policy is to kill queries "
-            "after {} seconds.".format(SQLLAB_TIMEOUT))
+            'after {} seconds.'.format(SQLLAB_TIMEOUT))
     except Exception as e:
         logging.exception(e)
         if conn is not None:
             conn.close()
         return handle_error(db_engine_spec.extract_error_message(e))
 
-    logging.info("Fetching cursor description")
+    logging.info('Fetching cursor description')
     cursor_description = cursor.description
 
     if conn is not None:
@@ -248,7 +248,7 @@ def execute_sql(
     })
     if store_results:
         key = '{}'.format(uuid.uuid4())
-        logging.info("Storing results in results backend, key: {}".format(key))
+        logging.info('Storing results in results backend, key: {}'.format(key))
         json_payload = json.dumps(payload, default=utils.json_iso_dttm_ser)
         results_backend.set(key, utils.zlib_compress(json_payload))
         query.results_key = key
diff --git a/superset/sql_parse.py b/superset/sql_parse.py
index 7fc31c0..d42e891 100644
--- a/superset/sql_parse.py
+++ b/superset/sql_parse.py
@@ -20,7 +20,7 @@ class SupersetQuery(object):
         self._table_names = set()
         self._alias_names = set()
         # TODO: multistatement support
-        logging.info("Parsing with sqlparse statement {}".format(self.sql))
+        logging.info('Parsing with sqlparse statement {}'.format(self.sql))
         self._parsed = sqlparse.parse(self.sql)
         for statement in self._parsed:
             self.__extract_from_token(statement)
@@ -50,7 +50,7 @@ class SupersetQuery(object):
     @staticmethod
     def __get_full_name(identifier):
         if len(identifier.tokens) > 1 and identifier.tokens[1].value == '.':
-            return "{}.{}".format(identifier.tokens[0].value,
+            return '{}.{}'.format(identifier.tokens[0].value,
                                   identifier.tokens[2].value)
         return identifier.get_real_name()
 
@@ -101,7 +101,7 @@ class SupersetQuery(object):
         sql = self.stripped()
         if overwrite:
             exec_sql = 'DROP TABLE IF EXISTS {table_name};\n'
-        exec_sql += "CREATE TABLE {table_name} AS \n{sql}"
+        exec_sql += 'CREATE TABLE {table_name} AS \n{sql}'
         return exec_sql.format(**locals())
 
     def __extract_from_token(self, token):
diff --git a/superset/stats_logger.py b/superset/stats_logger.py
index bbeadd7..9644f10 100644
--- a/superset/stats_logger.py
+++ b/superset/stats_logger.py
@@ -30,17 +30,17 @@ class BaseStatsLogger(object):
 class DummyStatsLogger(BaseStatsLogger):
     def incr(self, key):
         logging.debug(
-            Fore.CYAN + "[stats_logger] (incr) " + key + Style.RESET_ALL)
+            Fore.CYAN + '[stats_logger] (incr) ' + key + Style.RESET_ALL)
 
     def decr(self, key):
         logging.debug((
-            Fore.CYAN + "[stats_logger] (decr) " + key +
+            Fore.CYAN + '[stats_logger] (decr) ' + key +
             Style.RESET_ALL))
 
     def gauge(self, key, value):
         logging.debug((
-            Fore.CYAN + "[stats_logger] (gauge) "
-            "{key} | {value}" + Style.RESET_ALL).format(**locals()))
+            Fore.CYAN + '[stats_logger] (gauge) '
+            '{key} | {value}' + Style.RESET_ALL).format(**locals()))
 
 
 try:
diff --git a/superset/utils.py b/superset/utils.py
index f3f1a60..42f2da3 100644
--- a/superset/utils.py
+++ b/superset/utils.py
@@ -186,9 +186,9 @@ def parse_human_datetime(s):
     datetime.datetime(2015, 4, 3, 0, 0)
     >>> parse_human_datetime('2/3/1969')
     datetime.datetime(1969, 2, 3, 0, 0)
-    >>> parse_human_datetime("now") <= datetime.now()
+    >>> parse_human_datetime('now') <= datetime.now()
     True
-    >>> parse_human_datetime("yesterday") <= datetime.now()
+    >>> parse_human_datetime('yesterday') <= datetime.now()
     True
     >>> date.today() - timedelta(1) == parse_human_datetime('yesterday').date()
     True
@@ -205,7 +205,7 @@ def parse_human_datetime(s):
         try:
             cal = parsedatetime.Calendar()
             parsed_dttm, parsed_flags = cal.parseDT(s)
-            # when time is not extracted, we "reset to midnight"
+            # when time is not extracted, we 'reset to midnight'
             if parsed_flags & 2 == 0:
                 parsed_dttm = parsed_dttm.replace(hour=0, minute=0, second=0)
             dttm = dttm_from_timtuple(parsed_dttm.utctimetuple())
@@ -224,7 +224,7 @@ def parse_human_timedelta(s):
     """
     Returns ``datetime.datetime`` from natural language time deltas
 
-    >>> parse_human_datetime("now") <= datetime.now()
+    >>> parse_human_datetime('now') <= datetime.now()
     True
     """
     cal = parsedatetime.Calendar()
@@ -260,7 +260,7 @@ def datetime_f(dttm):
             dttm = dttm[11:]
         elif now_iso[:4] == dttm[:4]:
             dttm = dttm[5:]
-    return "<nobr>{}</nobr>".format(dttm)
+    return '<nobr>{}</nobr>'.format(dttm)
 
 
 def base_json_conv(obj):
@@ -298,7 +298,7 @@ def json_iso_dttm_ser(obj):
         obj = obj.isoformat()
     else:
         raise TypeError(
-            "Unserializable object {} of type {}".format(obj, type(obj)))
+            'Unserializable object {} of type {}'.format(obj, type(obj)))
     return obj
 
 
@@ -324,7 +324,7 @@ def json_int_dttm_ser(obj):
         obj = (obj - EPOCH.date()).total_seconds() * 1000
     else:
         raise TypeError(
-            "Unserializable object {} of type {}".format(obj, type(obj)))
+            'Unserializable object {} of type {}'.format(obj, type(obj)))
     return obj
 
 
@@ -343,7 +343,7 @@ def error_msg_from_exception(e):
                      created via create_engine.
     engine = create_engine('presto://localhost:3506/silver') -
       gives an e.message as the str(dict)
-    presto.connect("localhost", port=3506, catalog='silver') - as a dict.
+    presto.connect('localhost', port=3506, catalog='silver') - as a dict.
     The latter version is parsed correctly by this function.
     """
     msg = ''
@@ -351,7 +351,7 @@ def error_msg_from_exception(e):
         if isinstance(e.message, dict):
             msg = e.message.get('message')
         elif e.message:
-            msg = "{}".format(e.message)
+            msg = '{}'.format(e.message)
     return msg or '{}'.format(e)
 
 
@@ -384,13 +384,13 @@ def generic_find_constraint_name(table, columns, referenced, db):
 
 def get_datasource_full_name(database_name, datasource_name, schema=None):
     if not schema:
-        return "[{}].[{}]".format(database_name, datasource_name)
-    return "[{}].[{}].[{}]".format(database_name, schema, datasource_name)
+        return '[{}].[{}]'.format(database_name, datasource_name)
+    return '[{}].[{}].[{}]'.format(database_name, schema, datasource_name)
 
 
 def get_schema_perm(database, schema):
     if schema:
-        return "[{}].[{}]".format(database, schema)
+        return '[{}].[{}]'.format(database, schema)
 
 
 def validate_json(obj):
@@ -398,7 +398,7 @@ def validate_json(obj):
         try:
             json.loads(obj)
         except Exception:
-            raise SupersetException("JSON is not valid")
+            raise SupersetException('JSON is not valid')
 
 
 def table_has_constraint(table, name, db):
@@ -421,7 +421,7 @@ class timeout(object):
         self.error_message = error_message
 
     def handle_timeout(self, signum, frame):
-        logging.error("Process timed out")
+        logging.error('Process timed out')
         raise SupersetTimeoutException(self.error_message)
 
     def __enter__(self):
@@ -441,15 +441,15 @@ class timeout(object):
 
 
 def pessimistic_connection_handling(some_engine):
-    @event.listens_for(some_engine, "engine_connect")
+    @event.listens_for(some_engine, 'engine_connect')
     def ping_connection(connection, branch):
         if branch:
-            # "branch" refers to a sub-connection of a connection,
+            # 'branch' refers to a sub-connection of a connection,
             # we don't want to bother pinging on these.
             return
 
-        # turn off "close with result".  This flag is only used with
-        # "connectionless" execution, otherwise will be False in any case
+        # turn off 'close with result'.  This flag is only used with
+        # 'connectionless' execution, otherwise will be False in any case
         save_should_close_with_result = connection.should_close_with_result
         connection.should_close_with_result = False
 
@@ -461,7 +461,7 @@ def pessimistic_connection_handling(some_engine):
         except exc.DBAPIError as err:
             # catch SQLAlchemy's DBAPIError, which is a wrapper
             # for the DBAPI's exception.  It includes a .connection_invalidated
-            # attribute which specifies if this connection is a "disconnect"
+            # attribute which specifies if this connection is a 'disconnect'
             # condition, which is based on inspection of the original exception
             # by the dialect in use.
             if err.connection_invalidated:
@@ -473,7 +473,7 @@ def pessimistic_connection_handling(some_engine):
             else:
                 raise
         finally:
-            # restore "close with result"
+            # restore 'close with result'
             connection.should_close_with_result = save_should_close_with_result
 
 
@@ -514,11 +514,11 @@ def send_email_smtp(to, subject, html_content, config, files=None,
     msg = MIMEMultipart(mime_subtype)
     msg['Subject'] = subject
     msg['From'] = smtp_mail_from
-    msg['To'] = ", ".join(to)
+    msg['To'] = ', '.join(to)
     recipients = to
     if cc:
         cc = get_email_address_list(cc)
-        msg['CC'] = ", ".join(cc)
+        msg['CC'] = ', '.join(cc)
         recipients = recipients + cc
 
     if bcc:
@@ -532,11 +532,11 @@ def send_email_smtp(to, subject, html_content, config, files=None,
 
     for fname in files or []:
         basename = os.path.basename(fname)
-        with open(fname, "rb") as f:
+        with open(fname, 'rb') as f:
             msg.attach(
                 MIMEApplication(
                     f.read(),
-                    Content_Disposition='attachment; filename="%s"' % basename,
+                    Content_Disposition="attachment; filename='%s'" % basename,
                     Name=basename))
 
     send_MIME_email(smtp_mail_from, recipients, msg, config, dryrun=dryrun)
@@ -557,7 +557,7 @@ def send_MIME_email(e_from, e_to, mime_msg, config, dryrun=False):
             s.starttls()
         if SMTP_USER and SMTP_PASSWORD:
             s.login(SMTP_USER, SMTP_PASSWORD)
-        logging.info("Sent an alert email to " + str(e_to))
+        logging.info('Sent an alert email to ' + str(e_to))
         s.sendmail(e_from, e_to, mime_msg.as_string())
         s.quit()
     else:
@@ -601,11 +601,11 @@ def has_access(f):
             logging.warning(
                 LOGMSG_ERR_SEC_ACCESS_DENIED.format(permission_str,
                                                     self.__class__.__name__))
-            flash(as_unicode(FLAMSG_ERR_SEC_ACCESS_DENIED), "danger")
+            flash(as_unicode(FLAMSG_ERR_SEC_ACCESS_DENIED), 'danger')
         # adds next arg to forward to the original path once user is logged in.
         return redirect(
             url_for(
-                self.appbuilder.sm.auth_view.__class__.__name__ + ".login",
+                self.appbuilder.sm.auth_view.__class__.__name__ + '.login',
                 next=request.path))
 
     f._permission_name = permission_str
@@ -631,7 +631,7 @@ def zlib_compress(data):
     """
     if PY3K:
         if isinstance(data, str):
-            return zlib.compress(bytes(data, "utf-8"))
+            return zlib.compress(bytes(data, 'utf-8'))
         return zlib.compress(data)
     return zlib.compress(data)
 
@@ -649,8 +649,8 @@ def zlib_decompress_to_string(blob):
         if isinstance(blob, bytes):
             decompressed = zlib.decompress(blob)
         else:
-            decompressed = zlib.decompress(bytes(blob, "utf-8"))
-        return decompressed.decode("utf-8")
+            decompressed = zlib.decompress(bytes(blob, 'utf-8'))
+        return decompressed.decode('utf-8')
     return zlib.decompress(blob)
 
 
@@ -668,7 +668,7 @@ def get_celery_app(config):
 def merge_extra_filters(form_data):
     # extra_filters are temporary/contextual filters that are external
     # to the slice definition. We use those for dynamic interactive
-    # filters like the ones emitted by the "Filter Box" visualization
+    # filters like the ones emitted by the 'Filter Box' visualization
     if form_data.get('extra_filters'):
         # __form and __to are special extra_filters that target time
         # boundaries. The rest of extra_filters are simple
diff --git a/superset/views/annotations.py b/superset/views/annotations.py
index b43e97e..e11a412 100644
--- a/superset/views/annotations.py
+++ b/superset/views/annotations.py
@@ -20,15 +20,15 @@ class AnnotationModelView(SupersetModelView, DeleteMixin):  # noqa
 
     def pre_add(self, obj):
         if not obj.layer:
-            raise Exception("Annotation layer is required.")
+            raise Exception('Annotation layer is required.')
         if not obj.start_dttm and not obj.end_dttm:
-            raise Exception("Annotation start time or end time is required.")
+            raise Exception('Annotation start time or end time is required.')
         elif not obj.start_dttm:
             obj.start_dttm = obj.end_dttm
         elif not obj.end_dttm:
             obj.end_dttm = obj.start_dttm
         elif obj.end_dttm < obj.start_dttm:
-            raise Exception("Annotation end time must be no earlier than start time.")
+            raise Exception('Annotation end time must be no earlier than start time.')
 
     def pre_update(self, obj):
         self.pre_add(obj)
@@ -43,17 +43,17 @@ class AnnotationLayerModelView(SupersetModelView, DeleteMixin):
 
 appbuilder.add_view(
     AnnotationLayerModelView,
-    "Annotation Layers",
-    label=__("Annotation Layers"),
-    icon="fa-comment",
-    category="Manage",
-    category_label=__("Manage"),
+    'Annotation Layers',
+    label=__('Annotation Layers'),
+    icon='fa-comment',
+    category='Manage',
+    category_label=__('Manage'),
     category_icon='')
 appbuilder.add_view(
     AnnotationModelView,
-    "Annotations",
-    label=__("Annotations"),
-    icon="fa-comments",
-    category="Manage",
-    category_label=__("Manage"),
+    'Annotations',
+    label=__('Annotations'),
+    icon='fa-comments',
+    category='Manage',
+    category_label=__('Manage'),
     category_icon='')
diff --git a/superset/views/base.py b/superset/views/base.py
index cf0b2b9..7bc55d2 100644
--- a/superset/views/base.py
+++ b/superset/views/base.py
@@ -21,13 +21,13 @@ FRONTEND_CONF_KEYS = ('SUPERSET_WEBSERVER_TIMEOUT',)
 
 
 def get_error_msg():
-    if conf.get("SHOW_STACKTRACE"):
+    if conf.get('SHOW_STACKTRACE'):
         error_msg = traceback.format_exc()
     else:
-        error_msg = "FATAL ERROR \n"
+        error_msg = 'FATAL ERROR \n'
         error_msg += (
-            "Stacktrace is hidden. Change the SHOW_STACKTRACE "
-            "configuration setting to enable it")
+            'Stacktrace is hidden. Change the SHOW_STACKTRACE '
+            'configuration setting to enable it')
     return error_msg
 
 
@@ -38,7 +38,7 @@ def json_error_response(msg=None, status=500, stacktrace=None, payload=None):
             payload['stacktrace'] = stacktrace
     return Response(
         json.dumps(payload, default=utils.json_iso_dttm_ser),
-        status=status, mimetype="application/json")
+        status=status, mimetype='application/json')
 
 
 def api(f):
@@ -57,7 +57,7 @@ def api(f):
 
 
 def get_datasource_exist_error_mgs(full_name):
-    return __("Datasource %(name)s already exists", name=full_name)
+    return __('Datasource %(name)s already exists', name=full_name)
 
 
 def get_user_roles():
@@ -76,26 +76,26 @@ class BaseSupersetView(BaseView):
 
     def all_datasource_access(self, user=None):
         return self.can_access(
-            "all_datasource_access", "all_datasource_access", user=user)
+            'all_datasource_access', 'all_datasource_access', user=user)
 
     def database_access(self, database, user=None):
         return (
             self.can_access(
-                "all_database_access", "all_database_access", user=user) or
-            self.can_access("database_access", database.perm, user=user)
+                'all_database_access', 'all_database_access', user=user) or
+            self.can_access('database_access', database.perm, user=user)
         )
 
     def schema_access(self, datasource, user=None):
         return (
             self.database_access(datasource.database, user=user) or
             self.all_datasource_access(user=user) or
-            self.can_access("schema_access", datasource.schema_perm, user=user)
+            self.can_access('schema_access', datasource.schema_perm, user=user)
         )
 
     def datasource_access(self, datasource, user=None):
         return (
             self.schema_access(datasource, user=user) or
-            self.can_access("datasource_access", datasource.perm, user=user)
+            self.can_access('datasource_access', datasource.perm, user=user)
         )
 
     def datasource_access_by_name(
@@ -110,13 +110,13 @@ class BaseSupersetView(BaseView):
         datasources = ConnectorRegistry.query_datasources_by_name(
             db.session, database, datasource_name, schema=schema)
         for datasource in datasources:
-            if self.can_access("datasource_access", datasource.perm):
+            if self.can_access('datasource_access', datasource.perm):
                 return True
         return False
 
     def datasource_access_by_fullname(
             self, database, full_table_name, schema):
-        table_name_pieces = full_table_name.split(".")
+        table_name_pieces = full_table_name.split('.')
         if len(table_name_pieces) == 2:
             table_schema = table_name_pieces[0]
             table_name = table_name_pieces[1]
@@ -234,7 +234,7 @@ class DeleteMixin(object):
         try:
             self.pre_delete(item)
         except Exception as e:
-            flash(str(e), "danger")
+            flash(str(e), 'danger')
         else:
             view_menu = sm.find_view_menu(item.get_perm())
             pvs = sm.get_session.query(sm.permissionview_model).filter_by(
@@ -266,10 +266,10 @@ class DeleteMixin(object):
             self.update_redirect()
 
     @action(
-        "muldelete",
-        __("Delete"),
-        __("Delete all Really?"),
-        "fa-trash",
+        'muldelete',
+        __('Delete'),
+        __('Delete all Really?'),
+        'fa-trash',
         single=False,
     )
     def muldelete(self, items):
@@ -279,7 +279,7 @@ class DeleteMixin(object):
             try:
                 self.pre_delete(item)
             except Exception as e:
-                flash(str(e), "danger")
+                flash(str(e), 'danger')
             else:
                 self._delete(item.id)
         self.update_redirect()
diff --git a/superset/views/core.py b/superset/views/core.py
index c106556..e5ae708 100755
--- a/superset/views/core.py
+++ b/superset/views/core.py
@@ -52,26 +52,26 @@ DAR = models.DatasourceAccessRequest
 
 
 ALL_DATASOURCE_ACCESS_ERR = __(
-    "This endpoint requires the `all_datasource_access` permission")
-DATASOURCE_MISSING_ERR = __("The datasource seems to have been deleted")
+    'This endpoint requires the `all_datasource_access` permission')
+DATASOURCE_MISSING_ERR = __('The datasource seems to have been deleted')
 ACCESS_REQUEST_MISSING_ERR = __(
-    "The access requests seem to have been deleted")
-USER_MISSING_ERR = __("The user seems to have been deleted")
+    'The access requests seem to have been deleted')
+USER_MISSING_ERR = __('The user seems to have been deleted')
 DATASOURCE_ACCESS_ERR = __("You don't have access to this datasource")
 
 
 def get_database_access_error_msg(database_name):
-    return __("This view requires the database %(name)s or "
-              "`all_datasource_access` permission", name=database_name)
+    return __('This view requires the database %(name)s or '
+              '`all_datasource_access` permission', name=database_name)
 
 
 def get_datasource_access_error_msg(datasource_name):
-    return __("This endpoint requires the datasource %(name)s, database or "
-              "`all_datasource_access` permission", name=datasource_name)
+    return __('This endpoint requires the datasource %(name)s, database or '
+              '`all_datasource_access` permission', name=datasource_name)
 
 
 def json_success(json_msg, status=200):
-    return Response(json_msg, status=status, mimetype="application/json")
+    return Response(json_msg, status=status, mimetype='application/json')
 
 
 def is_owner(obj, user):
@@ -158,10 +158,10 @@ class DashboardFilter(SupersetFilter):
 
 
 def generate_download_headers(extension):
-    filename = datetime.now().strftime("%Y%m%d_%H%M%S")
-    content_disp = "attachment; filename={}.{}".format(filename, extension)
+    filename = datetime.now().strftime('%Y%m%d_%H%M%S')
+    content_disp = 'attachment; filename={}.{}'.format(filename, extension)
     headers = {
-        "Content-Disposition": content_disp,
+        'Content-Disposition': content_disp,
     }
     return headers
 
@@ -201,63 +201,63 @@ class DatabaseView(SupersetModelView, DeleteMixin):  # noqa
         'changed_by',
         'changed_on',
     ]
-    add_template = "superset/models/database/add.html"
-    edit_template = "superset/models/database/edit.html"
+    add_template = 'superset/models/database/add.html'
+    edit_template = 'superset/models/database/edit.html'
     base_order = ('changed_on', 'desc')
     description_columns = {
         'sqlalchemy_uri': utils.markdown(
-            "Refer to the "
-            "[SqlAlchemy docs]"
-            "(http://docs.sqlalchemy.org/en/rel_1_0/core/engines.html#"
-            "database-urls) "
-            "for more information on how to structure your URI.", True),
-        'expose_in_sqllab': _("Expose this DB in SQL Lab"),
+            'Refer to the '
+            '[SqlAlchemy docs]'
+            '(http://docs.sqlalchemy.org/en/rel_1_0/core/engines.html#'
+            'database-urls) '
+            'for more information on how to structure your URI.', True),
+        'expose_in_sqllab': _('Expose this DB in SQL Lab'),
         'allow_run_sync': _(
-            "Allow users to run synchronous queries, this is the default "
-            "and should work well for queries that can be executed "
-            "within a web request scope (<~1 minute)"),
+            'Allow users to run synchronous queries, this is the default '
+            'and should work well for queries that can be executed '
+            'within a web request scope (<~1 minute)'),
         'allow_run_async': _(
-            "Allow users to run queries, against an async backend. "
-            "This assumes that you have a Celery worker setup as well "
-            "as a results backend."),
-        'allow_ctas': _("Allow CREATE TABLE AS option in SQL Lab"),
+            'Allow users to run queries, against an async backend. '
+            'This assumes that you have a Celery worker setup as well '
+            'as a results backend.'),
+        'allow_ctas': _('Allow CREATE TABLE AS option in SQL Lab'),
         'allow_dml': _(
-            "Allow users to run non-SELECT statements "
-            "(UPDATE, DELETE, CREATE, ...) "
-            "in SQL Lab"),
+            'Allow users to run non-SELECT statements '
+            '(UPDATE, DELETE, CREATE, ...) '
+            'in SQL Lab'),
         'force_ctas_schema': _(
-            "When allowing CREATE TABLE AS option in SQL Lab, "
-            "this option forces the table to be created in this schema"),
+            'When allowing CREATE TABLE AS option in SQL Lab, '
+            'this option forces the table to be created in this schema'),
         'extra': utils.markdown(
-            "JSON string containing extra configuration elements. "
-            "The ``engine_params`` object gets unpacked into the "
-            "[sqlalchemy.create_engine]"
-            "(http://docs.sqlalchemy.org/en/latest/core/engines.html#"
-            "sqlalchemy.create_engine) call, while the ``metadata_params`` "
-            "gets unpacked into the [sqlalchemy.MetaData]"
-            "(http://docs.sqlalchemy.org/en/rel_1_0/core/metadata.html"
-            "#sqlalchemy.schema.MetaData) call. ", True),
+            'JSON string containing extra configuration elements. '
+            'The ``engine_params`` object gets unpacked into the '
+            '[sqlalchemy.create_engine]'
+            '(http://docs.sqlalchemy.org/en/latest/core/engines.html#'
+            'sqlalchemy.create_engine) call, while the ``metadata_params`` '
+            'gets unpacked into the [sqlalchemy.MetaData]'
+            '(http://docs.sqlalchemy.org/en/rel_1_0/core/metadata.html'
+            '#sqlalchemy.schema.MetaData) call. ', True),
         'impersonate_user': _(
-            "If Presto, all the queries in SQL Lab are going to be executed as the "
-            "currently logged on user who must have permission to run them.<br/>"
-            "If Hive and hive.server2.enable.doAs is enabled, will run the queries as "
-            "service account, but impersonate the currently logged on user "
-            "via hive.server2.proxy.user property."),
+            'If Presto, all the queries in SQL Lab are going to be executed as the '
+            'currently logged on user who must have permission to run them.<br/>'
+            'If Hive and hive.server2.enable.doAs is enabled, will run the queries as '
+            'service account, but impersonate the currently logged on user '
+            'via hive.server2.proxy.user property.'),
     }
     label_columns = {
-        'expose_in_sqllab': _("Expose in SQL Lab"),
-        'allow_ctas': _("Allow CREATE TABLE AS"),
-        'allow_dml': _("Allow DML"),
-        'force_ctas_schema': _("CTAS Schema"),
-        'database_name': _("Database"),
-        'creator': _("Creator"),
-        'changed_on_': _("Last Changed"),
-        'sqlalchemy_uri': _("SQLAlchemy URI"),
-        'cache_timeout': _("Cache Timeout"),
-        'extra': _("Extra"),
-        'allow_run_sync': _("Allow Run Sync"),
-        'allow_run_async': _("Allow Run Async"),
-        'impersonate_user': _("Impersonate the logged on user"),
+        'expose_in_sqllab': _('Expose in SQL Lab'),
+        'allow_ctas': _('Allow CREATE TABLE AS'),
+        'allow_dml': _('Allow DML'),
+        'force_ctas_schema': _('CTAS Schema'),
+        'database_name': _('Database'),
+        'creator': _('Creator'),
+        'changed_on_': _('Last Changed'),
+        'sqlalchemy_uri': _('SQLAlchemy URI'),
+        'cache_timeout': _('Cache Timeout'),
+        'extra': _('Extra'),
+        'allow_run_sync': _('Allow Run Sync'),
+        'allow_run_async': _('Allow Run Async'),
+        'impersonate_user': _('Impersonate the logged on user'),
     }
 
     def pre_add(self, db):
@@ -276,21 +276,21 @@ class DatabaseView(SupersetModelView, DeleteMixin):  # noqa
 
 appbuilder.add_link(
     'Import Dashboards',
-    label=__("Import Dashboards"),
+    label=__('Import Dashboards'),
     href='/superset/import_dashboards',
-    icon="fa-cloud-upload",
+    icon='fa-cloud-upload',
     category='Manage',
-    category_label=__("Manage"),
+    category_label=__('Manage'),
     category_icon='fa-wrench',)
 
 
 appbuilder.add_view(
     DatabaseView,
-    "Databases",
-    label=__("Databases"),
-    icon="fa-database",
-    category="Sources",
-    category_label=__("Sources"),
+    'Databases',
+    label=__('Databases'),
+    icon='fa-database',
+    category='Sources',
+    category_label=__('Sources'),
     category_icon='fa-database',)
 
 
@@ -320,21 +320,21 @@ class AccessRequestsModelView(SupersetModelView, DeleteMixin):
     order_columns = ['created_on']
     base_order = ('changed_on', 'desc')
     label_columns = {
-        'username': _("User"),
-        'user_roles': _("User Roles"),
-        'database': _("Database URL"),
-        'datasource_link': _("Datasource"),
-        'roles_with_datasource': _("Roles to grant"),
-        'created_on': _("Created On"),
+        'username': _('User'),
+        'user_roles': _('User Roles'),
+        'database': _('Database URL'),
+        'datasource_link': _('Datasource'),
+        'roles_with_datasource': _('Roles to grant'),
+        'created_on': _('Created On'),
     }
 
 
 appbuilder.add_view(
     AccessRequestsModelView,
-    "Access requests",
-    label=__("Access requests"),
-    category="Security",
-    category_label=__("Security"),
+    'Access requests',
+    label=__('Access requests'),
+    category='Security',
+    category_label=__('Security'),
     icon='fa-table',)
 
 
@@ -362,33 +362,33 @@ class SliceModelView(SupersetModelView, DeleteMixin):  # noqa
     base_order = ('changed_on', 'desc')
     description_columns = {
         'description': Markup(
-            "The content here can be displayed as widget headers in the "
-            "dashboard view. Supports "
-            "<a href='https://daringfireball.net/projects/markdown/'>"
-            "markdown</a>"),
+            'The content here can be displayed as widget headers in the '
+            'dashboard view. Supports '
+            '<a href="https://daringfireball.net/projects/markdown/"">'
+            'markdown</a>'),
         'params': _(
-            "These parameters are generated dynamically when clicking "
-            "the save or overwrite button in the explore view. This JSON "
-            "object is exposed here for reference and for power users who may "
-            "want to alter specific parameters.",
+            'These parameters are generated dynamically when clicking '
+            'the save or overwrite button in the explore view. This JSON '
+            'object is exposed here for reference and for power users who may '
+            'want to alter specific parameters.',
         ),
         'cache_timeout': _(
-            "Duration (in seconds) of the caching timeout for this slice."),
+            'Duration (in seconds) of the caching timeout for this slice.'),
     }
     base_filters = [['id', SliceFilter, lambda: []]]
     label_columns = {
-        'cache_timeout': _("Cache Timeout"),
-        'creator': _("Creator"),
-        'dashboards': _("Dashboards"),
-        'datasource_link': _("Datasource"),
-        'description': _("Description"),
-        'modified': _("Last Modified"),
-        'owners': _("Owners"),
-        'params': _("Parameters"),
-        'slice_link': _("Slice"),
-        'slice_name': _("Name"),
-        'table': _("Table"),
-        'viz_type': _("Visualization Type"),
+        'cache_timeout': _('Cache Timeout'),
+        'creator': _('Creator'),
+        'dashboards': _('Dashboards'),
+        'datasource_link': _('Datasource'),
+        'description': _('Description'),
+        'modified': _('Last Modified'),
+        'owners': _('Owners'),
+        'params': _('Parameters'),
+        'slice_link': _('Slice'),
+        'slice_name': _('Name'),
+        'table': _('Table'),
+        'viz_type': _('Visualization Type'),
     }
 
     def pre_add(self, obj):
@@ -410,19 +410,19 @@ class SliceModelView(SupersetModelView, DeleteMixin):  # noqa
             for d in datasources
         ]
         return self.render_template(
-            "superset/add_slice.html",
+            'superset/add_slice.html',
             bootstrap_data=json.dumps({
-                'datasources': sorted(datasources, key=lambda d: d["label"]),
+                'datasources': sorted(datasources, key=lambda d: d['label']),
             }),
         )
 
 
 appbuilder.add_view(
     SliceModelView,
-    "Slices",
-    label=__("Slices"),
-    icon="fa-bar-chart",
-    category="",
+    'Slices',
+    label=__('Slices'),
+    icon='fa-bar-chart',
+    category='',
     category_icon='',)
 
 
@@ -467,21 +467,21 @@ class DashboardModelView(SupersetModelView, DeleteMixin):  # noqa
     base_order = ('changed_on', 'desc')
     description_columns = {
         'position_json': _(
-            "This json object describes the positioning of the widgets in "
-            "the dashboard. It is dynamically generated when adjusting "
-            "the widgets size and positions by using drag & drop in "
-            "the dashboard view"),
+            'This json object describes the positioning of the widgets in '
+            'the dashboard. It is dynamically generated when adjusting '
+            'the widgets size and positions by using drag & drop in '
+            'the dashboard view'),
         'css': _(
-            "The css for individual dashboards can be altered here, or "
-            "in the dashboard view where changes are immediately "
-            "visible"),
-        'slug': _("To get a readable URL for your dashboard"),
+            'The css for individual dashboards can be altered here, or '
+            'in the dashboard view where changes are immediately '
+            'visible'),
+        'slug': _('To get a readable URL for your dashboard'),
         'json_metadata': _(
-            "This JSON object is generated dynamically when clicking "
-            "the save or overwrite button in the dashboard view. It "
-            "is exposed here for reference and for power users who may "
-            "want to alter specific parameters."),
-        'owners': _("Owners is a list of users who can alter the dashboard."),
+            'This JSON object is generated dynamically when clicking '
+            'the save or overwrite button in the dashboard view. It '
+            'is exposed here for reference and for power users who may '
+            'want to alter specific parameters.'),
+        'owners': _('Owners is a list of users who can alter the dashboard.'),
     }
     base_filters = [['slice', DashboardFilter, lambda: []]]
     add_form_query_rel_fields = {
@@ -489,23 +489,23 @@ class DashboardModelView(SupersetModelView, DeleteMixin):  # noqa
     }
     edit_form_query_rel_fields = add_form_query_rel_fields
     label_columns = {
-        'dashboard_link': _("Dashboard"),
-        'dashboard_title': _("Title"),
-        'slug': _("Slug"),
-        'slices': _("Slices"),
-        'owners': _("Owners"),
-        'creator': _("Creator"),
-        'modified': _("Modified"),
-        'position_json': _("Position JSON"),
-        'css': _("CSS"),
-        'json_metadata': _("JSON Metadata"),
-        'table_names': _("Underlying Tables"),
+        'dashboard_link': _('Dashboard'),
+        'dashboard_title': _('Title'),
+        'slug': _('Slug'),
+        'slices': _('Slices'),
+        'owners': _('Owners'),
+        'creator': _('Creator'),
+        'modified': _('Modified'),
+        'position_json': _('Position JSON'),
+        'css': _('CSS'),
+        'json_metadata': _('JSON Metadata'),
+        'table_names': _('Underlying Tables'),
     }
 
     def pre_add(self, obj):
         obj.slug = obj.slug.strip() or None
         if obj.slug:
-            obj.slug = obj.slug.replace(" ", "-")
+            obj.slug = obj.slug.replace(' ', '-')
             obj.slug = re.sub(r'\W+', '', obj.slug)
         if g.user not in obj.owners:
             obj.owners.append(g.user)
@@ -522,7 +522,7 @@ class DashboardModelView(SupersetModelView, DeleteMixin):  # noqa
     def pre_delete(self, obj):
         check_ownership(obj)
 
-    @action("mulexport", __("Export"), __("Export dashboards?"), "fa-database")
+    @action('mulexport', __('Export'), __('Export dashboards?'), 'fa-database')
     def mulexport(self, items):
         if not isinstance(items, list):
             items = [items]
@@ -530,14 +530,14 @@ class DashboardModelView(SupersetModelView, DeleteMixin):  # noqa
         return redirect(
             '/dashboardmodelview/export_dashboards_form?{}'.format(ids[1:]))
 
-    @expose("/export_dashboards_form")
+    @expose('/export_dashboards_form')
     def download_dashboards(self):
         if request.args.get('action') == 'go':
             ids = request.args.getlist('id')
             return Response(
                 models.Dashboard.export_dashboards(ids),
-                headers=generate_download_headers("pickle"),
-                mimetype="application/text")
+                headers=generate_download_headers('pickle'),
+                mimetype='application/text')
         return self.render_template(
             'superset/export_dashboards.html',
             dashboards_url='/dashboardmodelview/list',
@@ -546,9 +546,9 @@ class DashboardModelView(SupersetModelView, DeleteMixin):  # noqa
 
 appbuilder.add_view(
     DashboardModelView,
-    "Dashboards",
-    label=__("Dashboards"),
-    icon="fa-dashboard",
+    'Dashboards',
+    label=__('Dashboards'),
+    icon='fa-dashboard',
     category='',
     category_icon='',)
 
@@ -572,35 +572,35 @@ class LogModelView(SupersetModelView):
     edit_columns = ('user', 'action', 'dttm', 'json')
     base_order = ('dttm', 'desc')
     label_columns = {
-        'user': _("User"),
-        'action': _("Action"),
-        'dttm': _("dttm"),
-        'json': _("JSON"),
+        'user': _('User'),
+        'action': _('Action'),
+        'dttm': _('dttm'),
+        'json': _('JSON'),
     }
 
 
 appbuilder.add_view(
     LogModelView,
-    "Action Log",
-    label=__("Action Log"),
-    category="Security",
-    category_label=__("Security"),
-    icon="fa-list-ol")
+    'Action Log',
+    label=__('Action Log'),
+    category='Security',
+    category_label=__('Security'),
+    icon='fa-list-ol')
 
 
 @app.route('/health')
 def health():
-    return "OK"
+    return 'OK'
 
 
 @app.route('/healthcheck')
 def healthcheck():
-    return "OK"
+    return 'OK'
 
 
 @app.route('/ping')
 def ping():
-    return "OK"
+    return 'OK'
 
 
 class KV(BaseSupersetView):
@@ -608,7 +608,7 @@ class KV(BaseSupersetView):
     """Used for storing and retrieving key value pairs"""
 
     @log_this
-    @expose("/store/", methods=['POST'])
+    @expose('/store/', methods=['POST'])
     def store(self):
         try:
             value = request.form.get('data')
@@ -622,7 +622,7 @@ class KV(BaseSupersetView):
             status=200)
 
     @log_this
-    @expose("/<key_id>/", methods=['GET'])
+    @expose('/<key_id>/', methods=['GET'])
     def get_value(self, key_id):
         kv = None
         try:
@@ -640,30 +640,30 @@ class R(BaseSupersetView):
     """used for short urls"""
 
     @log_this
-    @expose("/<url_id>")
+    @expose('/<url_id>')
     def index(self, url_id):
         url = db.session.query(models.Url).filter_by(id=url_id).first()
         if url:
             return redirect('/' + url.url)
         else:
-            flash("URL to nowhere...", "danger")
+            flash('URL to nowhere...', 'danger')
             return redirect('/')
 
     @log_this
-    @expose("/shortner/", methods=['POST', 'GET'])
+    @expose('/shortner/', methods=['POST', 'GET'])
     def shortner(self):
         url = request.form.get('data')
         obj = models.Url(url=url)
         db.session.add(obj)
         db.session.commit()
-        return("http://{request.headers[Host]}/r/{obj.id}".format(
+        return('http://{request.headers[Host]}/r/{obj.id}'.format(
             request=request, obj=obj))
 
-    @expose("/msg/")
+    @expose('/msg/')
     def msg(self):
         """Redirects to specified url while flash a message"""
-        flash(Markup(request.args.get("msg")), "info")
-        return redirect(request.args.get("url"))
+        flash(Markup(request.args.get('msg')), 'info')
+        return redirect(request.args.get('url'))
 
 
 appbuilder.add_view_no_menu(R)
@@ -673,7 +673,7 @@ class Superset(BaseSupersetView):
     """The base views for Superset!"""
     @api
     @has_access_api
-    @expose("/update_role/", methods=['POST'])
+    @expose('/update_role/', methods=['POST'])
     def update_role(self):
         """Assigns a list of found users to the given role."""
         data = request.get_json(force=True)
@@ -699,7 +699,7 @@ class Superset(BaseSupersetView):
             user_data = user_data_dict[username]
             user = sm.find_user(email=user_data['email'])
             if not user:
-                logging.info("Adding user: {}.".format(user_data))
+                logging.info('Adding user: {}.'.format(user_data))
                 sm.add_user(
                     username=user_data['username'],
                     first_name=user_data['first_name'],
@@ -727,10 +727,10 @@ class Superset(BaseSupersetView):
         return Response(
             json.dumps(obj, default=utils.json_int_dttm_ser),
             status=status,
-            mimetype="application/json")
+            mimetype='application/json')
 
     @has_access_api
-    @expose("/datasources/")
+    @expose('/datasources/')
     def datasources(self):
         datasources = ConnectorRegistry.get_all_datasources(db.session)
         datasources = [o.short_data for o in datasources]
@@ -738,7 +738,7 @@ class Superset(BaseSupersetView):
         return self.json_response(datasources)
 
     @has_access_api
-    @expose("/override_role_permissions/", methods=['POST'])
+    @expose('/override_role_permissions/', methods=['POST'])
     def override_role_permissions(self):
         """Updates the role with the give datasource permissions.
 
@@ -792,7 +792,7 @@ class Superset(BaseSupersetView):
 
     @log_this
     @has_access
-    @expose("/request_access/")
+    @expose('/request_access/')
     def request_access(self):
         datasources = set()
         dashboard_id = request.args.get('dashboard_id')
@@ -820,18 +820,18 @@ class Superset(BaseSupersetView):
                     datasource_type=datasource.type)
                 db.session.add(access_request)
                 db.session.commit()
-            flash(__("Access was requested"), "info")
+            flash(__('Access was requested'), 'info')
             return redirect('/')
 
         return self.render_template(
             'superset/request_access.html',
             datasources=datasources,
-            datasource_names=", ".join([o.name for o in datasources]),
+            datasource_names=', '.join([o.name for o in datasources]),
         )
 
     @log_this
     @has_access
-    @expose("/approve")
+    @expose('/approve')
     def approve(self):
         def clean_fulfilled_requests(session):
             for r in session.query(DAR).all():
@@ -854,12 +854,12 @@ class Superset(BaseSupersetView):
             datasource_type, datasource_id, session)
 
         if not datasource:
-            flash(DATASOURCE_MISSING_ERR, "alert")
+            flash(DATASOURCE_MISSING_ERR, 'alert')
             return json_error_response(DATASOURCE_MISSING_ERR)
 
         requested_by = sm.find_user(username=created_by_username)
         if not requested_by:
-            flash(USER_MISSING_ERR, "alert")
+            flash(USER_MISSING_ERR, 'alert')
             return json_error_response(USER_MISSING_ERR)
 
         requests = (
@@ -872,7 +872,7 @@ class Superset(BaseSupersetView):
         )
 
         if not requests:
-            flash(ACCESS_REQUEST_MISSING_ERR, "alert")
+            flash(ACCESS_REQUEST_MISSING_ERR, 'alert')
             return json_error_response(ACCESS_REQUEST_MISSING_ERR)
 
         # check if you can approve
@@ -882,32 +882,32 @@ class Superset(BaseSupersetView):
                 role = sm.find_role(role_to_grant)
                 requested_by.roles.append(role)
                 msg = __(
-                    "%(user)s was granted the role %(role)s that gives access "
-                    "to the %(datasource)s",
+                    '%(user)s was granted the role %(role)s that gives access '
+                    'to the %(datasource)s',
                     user=requested_by.username,
                     role=role_to_grant,
                     datasource=datasource.full_name)
                 utils.notify_user_about_perm_udate(
                     g.user, requested_by, role, datasource,
                     'email/role_granted.txt', app.config)
-                flash(msg, "info")
+                flash(msg, 'info')
 
             if role_to_extend:
                 perm_view = sm.find_permission_view_menu(
                     'email/datasource_access', datasource.perm)
                 role = sm.find_role(role_to_extend)
                 sm.add_permission_role(role, perm_view)
-                msg = __("Role %(r)s was extended to provide the access to "
-                         "the datasource %(ds)s", r=role_to_extend,
+                msg = __('Role %(r)s was extended to provide the access to '
+                         'the datasource %(ds)s', r=role_to_extend,
                          ds=datasource.full_name)
                 utils.notify_user_about_perm_udate(
                     g.user, requested_by, role, datasource,
                     'email/role_extended.txt', app.config)
-                flash(msg, "info")
+                flash(msg, 'info')
             clean_fulfilled_requests(session)
         else:
-            flash(__("You have no permission to approve this request"),
-                  "danger")
+            flash(__('You have no permission to approve this request'),
+                  'danger')
             return redirect('/accessrequestsmodelview/list/')
         for r in requests:
             session.delete(r)
@@ -916,17 +916,17 @@ class Superset(BaseSupersetView):
 
     def get_form_data(self):
         # get form data from url
-        if request.args.get("form_data"):
-            form_data = request.args.get("form_data")
-        elif request.form.get("form_data"):
+        if request.args.get('form_data'):
+            form_data = request.args.get('form_data')
+        elif request.form.get('form_data'):
             # Supporting POST as well as get
-            form_data = request.form.get("form_data")
+            form_data = request.form.get('form_data')
         else:
             form_data = '{}'
 
         d = json.loads(form_data)
 
-        if request.args.get("viz_type"):
+        if request.args.get('viz_type'):
             # Converting old URLs
             d = cast_form_data(request.args)
         return d
@@ -956,7 +956,7 @@ class Superset(BaseSupersetView):
             return viz_obj
 
     @has_access
-    @expose("/slice/<slice_id>/")
+    @expose('/slice/<slice_id>/')
     def slice(self, slice_id):
         viz_obj = self.get_viz(slice_id)
         endpoint = (
@@ -967,7 +967,7 @@ class Superset(BaseSupersetView):
                 parse.quote(json.dumps(viz_obj.form_data)),
             )
         )
-        if request.args.get("standalone") == "true":
+        if request.args.get('standalone') == 'true':
             endpoint += '&standalone=true'
         return redirect(endpoint)
 
@@ -983,11 +983,11 @@ class Superset(BaseSupersetView):
                 'language': viz_obj.datasource.query_language,
             }),
             status=200,
-            mimetype="application/json")
+            mimetype='application/json')
 
     @log_this
     @has_access_api
-    @expose("/explore_json/<datasource_type>/<datasource_id>/")
+    @expose('/explore_json/<datasource_type>/<datasource_id>/')
     def explore_json(self, datasource_type, datasource_id):
         try:
             viz_obj = self.get_viz(
@@ -1003,14 +1003,14 @@ class Superset(BaseSupersetView):
         if not self.datasource_access(viz_obj.datasource):
             return json_error_response(DATASOURCE_ACCESS_ERR, status=404)
 
-        if request.args.get("csv") == "true":
+        if request.args.get('csv') == 'true':
             return CsvResponse(
                 viz_obj.get_csv(),
                 status=200,
-                headers=generate_download_headers("csv"),
-                mimetype="application/csv")
+                headers=generate_download_headers('csv'),
+                mimetype='application/csv')
 
-        if request.args.get("query") == "true":
+        if request.args.get('query') == 'true':
             return self.get_query_string_response(viz_obj)
 
         payload = {}
@@ -1027,7 +1027,7 @@ class Superset(BaseSupersetView):
 
         return json_success(viz_obj.json_dumps(payload), status=status)
 
-    @expose("/import_dashboards", methods=['GET', 'POST'])
+    @expose('/import_dashboards', methods=['GET', 'POST'])
     @log_this
     def import_dashboards(self):
         """Overrides the dashboards using pickled instances from the file."""
@@ -1049,7 +1049,7 @@ class Superset(BaseSupersetView):
 
     @log_this
     @has_access
-    @expose("/explorev2/<datasource_type>/<datasource_id>/")
+    @expose('/explorev2/<datasource_type>/<datasource_id>/')
     def explorev2(self, datasource_type, datasource_id):
         return redirect(url_for(
             'Superset.explore',
@@ -1059,12 +1059,12 @@ class Superset(BaseSupersetView):
 
     @log_this
     @has_access
-    @expose("/explore/<datasource_type>/<datasource_id>/")
+    @expose('/explore/<datasource_type>/<datasource_id>/')
     def explore(self, datasource_type, datasource_id):
         form_data = self.get_form_data()
 
         datasource_id = int(datasource_id)
-        viz_type = form_data.get("viz_type")
+        viz_type = form_data.get('viz_type')
         slice_id = form_data.get('slice_id')
         user_id = g.user.get_id() if g.user else None
 
@@ -1076,13 +1076,13 @@ class Superset(BaseSupersetView):
         datasource = ConnectorRegistry.get_datasource(
             datasource_type, datasource_id, db.session)
         if not datasource:
-            flash(DATASOURCE_MISSING_ERR, "danger")
+            flash(DATASOURCE_MISSING_ERR, 'danger')
             return redirect(error_redirect)
 
         if not self.datasource_access(datasource):
             flash(
                 __(get_datasource_access_error_msg(datasource.name)),
-                "danger")
+                'danger')
             return redirect(
                 'superset/request_access/?'
                 'datasource_type={datasource_type}&'
@@ -1121,30 +1121,30 @@ class Superset(BaseSupersetView):
         # On explore, merge extra filters into the form data
         merge_extra_filters(form_data)
 
-        standalone = request.args.get("standalone") == "true"
+        standalone = request.args.get('standalone') == 'true'
         bootstrap_data = {
-            "can_add": slice_add_perm,
-            "can_download": slice_download_perm,
-            "can_overwrite": slice_overwrite_perm,
-            "datasource": datasource.data,
-            "form_data": form_data,
-            "datasource_id": datasource_id,
-            "datasource_type": datasource_type,
-            "slice": slc.data if slc else None,
-            "standalone": standalone,
-            "user_id": user_id,
-            "forced_height": request.args.get('height'),
+            'can_add': slice_add_perm,
+            'can_download': slice_download_perm,
+            'can_overwrite': slice_overwrite_perm,
+            'datasource': datasource.data,
+            'form_data': form_data,
+            'datasource_id': datasource_id,
+            'datasource_type': datasource_type,
+            'slice': slc.data if slc else None,
+            'standalone': standalone,
+            'user_id': user_id,
+            'forced_height': request.args.get('height'),
             'common': self.common_bootsrap_payload(),
         }
         table_name = datasource.table_name \
             if datasource_type == 'table' \
             else datasource.datasource_name
         if slc:
-            title = "[slice] " + slc.slice_name
+            title = '[slice] ' + slc.slice_name
         else:
-            title = "[explore] " + table_name
+            title = '[explore] ' + table_name
         return self.render_template(
-            "superset/basic.html",
+            'superset/basic.html',
             bootstrap_data=json.dumps(bootstrap_data),
             entry='explore',
             title=title,
@@ -1152,7 +1152,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/filter/<datasource_type>/<datasource_id>/<column>/")
+    @expose('/filter/<datasource_type>/<datasource_id>/<column>/')
     def filter(self, datasource_type, datasource_id, column):
         """
         Endpoint to retrieve values for specified column.
@@ -1209,29 +1209,29 @@ class Superset(BaseSupersetView):
                 .one()
             )
             flash(
-                "Slice [{}] was added to dashboard [{}]".format(
+                'Slice [{}] was added to dashboard [{}]'.format(
                     slc.slice_name,
                     dash.dashboard_title),
-                "info")
+                'info')
         elif request.args.get('add_to_dash') == 'new':
             dash = models.Dashboard(
                 dashboard_title=request.args.get('new_dashboard_name'),
                 owners=[g.user] if g.user else [])
             flash(
-                "Dashboard [{}] just got created and slice [{}] was added "
-                "to it".format(
+                'Dashboard [{}] just got created and slice [{}] was added '
+                'to it'.format(
                     dash.dashboard_title,
                     slc.slice_name),
-                "info")
+                'info')
 
         if dash and slc not in dash.slices:
             dash.slices.append(slc)
             db.session.commit()
 
         response = {
-            "can_add": slice_add_perm,
-            "can_download": slice_download_perm,
-            "can_overwrite": is_owner(slc, g.user),
+            'can_add': slice_add_perm,
+            'can_download': slice_download_perm,
+            'can_overwrite': is_owner(slc, g.user),
             'form_data': slc.form_data,
             'slice': slc.data,
         }
@@ -1243,21 +1243,21 @@ class Superset(BaseSupersetView):
 
     def save_slice(self, slc):
         session = db.session()
-        msg = "Slice [{}] has been saved".format(slc.slice_name)
+        msg = 'Slice [{}] has been saved'.format(slc.slice_name)
         session.add(slc)
         session.commit()
-        flash(msg, "info")
+        flash(msg, 'info')
 
     def overwrite_slice(self, slc):
         session = db.session()
         session.merge(slc)
         session.commit()
-        msg = "Slice [{}] has been overwritten".format(slc.slice_name)
-        flash(msg, "info")
+        msg = 'Slice [{}] has been overwritten'.format(slc.slice_name)
+        flash(msg, 'info')
 
     @api
     @has_access_api
-    @expose("/checkbox/<model_view>/<id_>/<attr>/<value>", methods=['GET'])
+    @expose('/checkbox/<model_view>/<id_>/<attr>/<value>', methods=['GET'])
     def checkbox(self, model_view, id_, attr, value):
         """endpoint for checking/unchecking any boolean in a sqla model"""
         modelview_to_model = {
@@ -1269,11 +1269,11 @@ class Superset(BaseSupersetView):
         if obj:
             setattr(obj, attr, value == 'true')
             db.session.commit()
-        return json_success("OK")
+        return json_success('OK')
 
     @api
     @has_access_api
-    @expose("/activity_per_day")
+    @expose('/activity_per_day')
     def activity_per_day(self):
         """endpoint to power the calendar heatmap on the welcome page"""
         Log = models.Log  # noqa
@@ -1291,7 +1291,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/schemas/<db_id>/")
+    @expose('/schemas/<db_id>/')
     def schemas(self, db_id):
         db_id = int(db_id)
         database = (
@@ -1304,11 +1304,11 @@ class Superset(BaseSupersetView):
         schemas = self.schemas_accessible_by_user(database, schemas)
         return Response(
             json.dumps({'schemas': schemas}),
-            mimetype="application/json")
+            mimetype='application/json')
 
     @api
     @has_access_api
-    @expose("/tables/<db_id>/<schema>/<substr>/")
+    @expose('/tables/<db_id>/<schema>/<substr>/')
     def tables(self, db_id, schema, substr):
         """Endpoint to fetch the list of tables for given database"""
         db_id = int(db_id)
@@ -1344,7 +1344,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/copy_dash/<dashboard_id>/", methods=['GET', 'POST'])
+    @expose('/copy_dash/<dashboard_id>/', methods=['GET', 'POST'])
     def copy_dash(self, dashboard_id):
         """Copy dashboard"""
         session = db.session()
@@ -1383,7 +1383,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/save_dash/<dashboard_id>/", methods=['GET', 'POST'])
+    @expose('/save_dash/<dashboard_id>/', methods=['GET', 'POST'])
     def save_dash(self, dashboard_id):
         """Save a dashboard's metadata"""
         session = db.session()
@@ -1396,7 +1396,7 @@ class Superset(BaseSupersetView):
         session.merge(dash)
         session.commit()
         session.close()
-        return "SUCCESS"
+        return 'SUCCESS'
 
     @staticmethod
     def _set_dash_metadata(dashboard, data):
@@ -1421,7 +1421,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/add_slices/<dashboard_id>/", methods=['POST'])
+    @expose('/add_slices/<dashboard_id>/', methods=['POST'])
     def add_slices(self, dashboard_id):
         """Add and save slices to a dashboard"""
         data = json.loads(request.form.get('data'))
@@ -1436,11 +1436,11 @@ class Superset(BaseSupersetView):
         session.merge(dash)
         session.commit()
         session.close()
-        return "SLICES ADDED"
+        return 'SLICES ADDED'
 
     @api
     @has_access_api
-    @expose("/testconn", methods=["POST", "GET"])
+    @expose('/testconn', methods=['POST', 'GET'])
     def testconn(self):
         """Tests a sqla connection"""
         try:
@@ -1470,7 +1470,7 @@ class Superset(BaseSupersetView):
                 db_engine.patch()
 
                 masked_url = database.get_password_masked_url_from_uri(uri)
-                logging.info("Superset.testconn(). Masked URL: {0}".format(masked_url))
+                logging.info('Superset.testconn(). Masked URL: {0}'.format(masked_url))
 
                 configuration.update(
                     db_engine.get_configuration_for_impersonation(uri,
@@ -1485,7 +1485,7 @@ class Superset(BaseSupersetView):
                 .get('connect_args', {}))
 
             if configuration:
-                connect_args["configuration"] = configuration
+                connect_args['configuration'] = configuration
 
             engine = create_engine(uri, connect_args=connect_args)
             engine.connect()
@@ -1493,12 +1493,12 @@ class Superset(BaseSupersetView):
         except Exception as e:
             logging.exception(e)
             return json_error_response((
-                "Connection failed!\n\n"
-                "The error message returned was:\n{}").format(e))
+                'Connection failed!\n\n'
+                'The error message returned was:\n{}').format(e))
 
     @api
     @has_access_api
-    @expose("/recent_activity/<user_id>/", methods=['GET'])
+    @expose('/recent_activity/<user_id>/', methods=['GET'])
     def recent_activity(self, user_id):
         """Recent activity (actions) for a given user"""
         M = models  # noqa
@@ -1543,7 +1543,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/csrf_token/", methods=['GET'])
+    @expose('/csrf_token/', methods=['GET'])
     def csrf_token(self):
         return Response(
             self.render_template('superset/csrf_token.json'),
@@ -1552,7 +1552,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/fave_dashboards_by_username/<username>/", methods=['GET'])
+    @expose('/fave_dashboards_by_username/<username>/', methods=['GET'])
     def fave_dashboards_by_username(self, username):
         """This lets us use a user's username to pull favourite dashboards"""
         user = sm.find_user(username=username)
@@ -1560,7 +1560,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/fave_dashboards/<user_id>/", methods=['GET'])
+    @expose('/fave_dashboards/<user_id>/', methods=['GET'])
     def fave_dashboards(self, user_id):
         qry = (
             db.session.query(
@@ -1599,7 +1599,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/created_dashboards/<user_id>/", methods=['GET'])
+    @expose('/created_dashboards/<user_id>/', methods=['GET'])
     def created_dashboards(self, user_id):
         Dash = models.Dashboard  # noqa
         qry = (
@@ -1628,7 +1628,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/created_slices/<user_id>/", methods=['GET'])
+    @expose('/created_slices/<user_id>/', methods=['GET'])
     def created_slices(self, user_id):
         """List of slices created by this user"""
         Slice = models.Slice  # noqa
@@ -1653,7 +1653,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/fave_slices/<user_id>/", methods=['GET'])
+    @expose('/fave_slices/<user_id>/', methods=['GET'])
     def fave_slices(self, user_id):
         """Favorite slices for a user"""
         qry = (
@@ -1692,7 +1692,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/warm_up_cache/", methods=['GET'])
+    @expose('/warm_up_cache/', methods=['GET'])
     def warm_up_cache(self):
         """Warms up the cache for the slice or table.
 
@@ -1706,13 +1706,13 @@ class Superset(BaseSupersetView):
 
         if not slice_id and not (table_name and db_name):
             return json_error_response(__(
-                "Malformed request. slice_id or table_name and db_name "
-                "arguments are expected"), status=400)
+                'Malformed request. slice_id or table_name and db_name '
+                'arguments are expected'), status=400)
         if slice_id:
             slices = session.query(models.Slice).filter_by(id=slice_id).all()
             if not slices:
                 return json_error_response(__(
-                    "Slice %(id)s not found", id=slice_id), status=404)
+                    'Slice %(id)s not found', id=slice_id), status=404)
         elif table_name and db_name:
             SqlaTable = ConnectorRegistry.sources['table']
             table = (
@@ -1737,10 +1737,10 @@ class Superset(BaseSupersetView):
             except Exception as e:
                 return json_error_response(utils.error_msg_from_exception(e))
         return json_success(json.dumps(
-            [{"slice_id": slc.id, "slice_name": slc.slice_name}
+            [{'slice_id': slc.id, 'slice_name': slc.slice_name}
              for slc in slices]))
 
-    @expose("/favstar/<class_name>/<obj_id>/<action>/")
+    @expose('/favstar/<class_name>/<obj_id>/<action>/')
     def favstar(self, class_name, obj_id, action):
         """Toggle favorite stars on Slices and Dashboard"""
         session = db.session()
@@ -1769,7 +1769,7 @@ class Superset(BaseSupersetView):
         return json_success(json.dumps({'count': count}))
 
     @has_access
-    @expose("/dashboard/<dashboard_id>/")
+    @expose('/dashboard/<dashboard_id>/')
     def dashboard(self, dashboard_id):
         """Server side rendering for a dashboard"""
         session = db.session()
@@ -1790,7 +1790,7 @@ class Superset(BaseSupersetView):
             if datasource and not self.datasource_access(datasource):
                 flash(
                     __(get_datasource_access_error_msg(datasource.name)),
-                    "danger")
+                    'danger')
                 return redirect(
                     'superset/request_access/?'
                     'dashboard_id={dash.id}&'.format(**locals()))
@@ -1805,7 +1805,7 @@ class Superset(BaseSupersetView):
         dash_save_perm = \
             dash_edit_perm and self.can_access('can_save_dash', 'Superset')
 
-        standalone_mode = request.args.get("standalone") == "true"
+        standalone_mode = request.args.get('standalone') == 'true'
 
         dashboard_data = dash.data
         dashboard_data.update({
@@ -1822,7 +1822,7 @@ class Superset(BaseSupersetView):
         }
 
         return self.render_template(
-            "superset/dashboard.html",
+            'superset/dashboard.html',
             entry='dashboard',
             standalone_mode=standalone_mode,
             title='[dashboard] ' + dash.dashboard_title,
@@ -1830,7 +1830,7 @@ class Superset(BaseSupersetView):
         )
 
     @has_access
-    @expose("/sync_druid/", methods=['POST'])
+    @expose('/sync_druid/', methods=['POST'])
     @log_this
     def sync_druid_source(self):
         """Syncs the druid datasource in main db with the provided config.
@@ -1848,9 +1848,9 @@ class Superset(BaseSupersetView):
             other fields will be ignored.
 
             Example: {
-                "name": "test_click",
-                "metrics_spec": [{"type": "count", "name": "count"}],
-                "dimensions": ["affiliate_id", "campaign", "first_seen"]
+                'name': 'test_click',
+                'metrics_spec': [{'type': 'count', 'name': 'count'}],
+                'dimensions': ['affiliate_id', 'campaign', 'first_seen']
             }
         """
         payload = request.get_json(force=True)
@@ -1863,7 +1863,7 @@ class Superset(BaseSupersetView):
         DruidCluster = DruidDatasource.cluster_class
         if not user:
             err_msg = __("Can't find User '%(name)s', please ask your admin "
-                         "to create one.", name=user_name)
+                         'to create one.', name=user_name)
             logging.error(err_msg)
             return json_error_response(err_msg)
         cluster = db.session.query(DruidCluster).filter_by(
@@ -1882,7 +1882,7 @@ class Superset(BaseSupersetView):
         return Response(status=201)
 
     @has_access
-    @expose("/sqllab_viz/", methods=['POST'])
+    @expose('/sqllab_viz/', methods=['POST'])
     @log_this
     def sqllab_viz(self):
         SqlaTable = ConnectorRegistry.sources['table']
@@ -1922,19 +1922,19 @@ class Superset(BaseSupersetView):
             if agg:
                 if agg == 'count_distinct':
                     metrics.append(SqlMetric(
-                        metric_name="{agg}__{column_name}".format(**locals()),
-                        expression="COUNT(DISTINCT {column_name})"
+                        metric_name='{agg}__{column_name}'.format(**locals()),
+                        expression='COUNT(DISTINCT {column_name})'
                         .format(**locals()),
                     ))
                 else:
                     metrics.append(SqlMetric(
-                        metric_name="{agg}__{column_name}".format(**locals()),
-                        expression="{agg}({column_name})".format(**locals()),
+                        metric_name='{agg}__{column_name}'.format(**locals()),
+                        expression='{agg}({column_name})'.format(**locals()),
                     ))
         if not metrics:
             metrics.append(SqlMetric(
-                metric_name="count".format(**locals()),
-                expression="count(*)".format(**locals()),
+                metric_name='count'.format(**locals()),
+                expression='count(*)'.format(**locals()),
             ))
         table.columns = cols
         table.metrics = metrics
@@ -1944,7 +1944,7 @@ class Superset(BaseSupersetView):
         }))
 
     @has_access
-    @expose("/table/<database_id>/<table_name>/<schema>/")
+    @expose('/table/<database_id>/<table_name>/<schema>/')
     @log_this
     def table(self, database_id, table_name, schema):
         schema = utils.js_string_to_python(schema)
@@ -1973,7 +1973,7 @@ class Superset(BaseSupersetView):
         keys += indexes
 
         for col in t:
-            dtype = ""
+            dtype = ''
             try:
                 dtype = '{}'.format(col['type'])
             except Exception:
@@ -1999,7 +1999,7 @@ class Superset(BaseSupersetView):
         return json_success(json.dumps(tbl))
 
     @has_access
-    @expose("/extra_table_metadata/<database_id>/<table_name>/<schema>/")
+    @expose('/extra_table_metadata/<database_id>/<table_name>/<schema>/')
     @log_this
     def extra_table_metadata(self, database_id, table_name, schema):
         schema = utils.js_string_to_python(schema)
@@ -2009,32 +2009,32 @@ class Superset(BaseSupersetView):
         return json_success(json.dumps(payload))
 
     @has_access
-    @expose("/select_star/<database_id>/<table_name>/")
+    @expose('/select_star/<database_id>/<table_name>/')
     @log_this
     def select_star(self, database_id, table_name):
         mydb = db.session.query(
             models.Database).filter_by(id=database_id).first()
         return self.render_template(
-            "superset/ajah.html",
+            'superset/ajah.html',
             content=mydb.select_star(table_name, show_cols=True),
         )
 
-    @expose("/theme/")
+    @expose('/theme/')
     def theme(self):
         return self.render_template('superset/theme.html')
 
     @has_access_api
-    @expose("/cached_key/<key>/")
+    @expose('/cached_key/<key>/')
     @log_this
     def cached_key(self, key):
         """Returns a key from the cache"""
         resp = cache.get(key)
         if resp:
             return resp
-        return "nope"
+        return 'nope'
 
     @has_access_api
-    @expose("/results/<key>/")
+    @expose('/results/<key>/')
     @log_this
     def results(self, key):
         """Serves a key off of the results backend"""
@@ -2044,8 +2044,8 @@ class Superset(BaseSupersetView):
         blob = results_backend.get(key)
         if not blob:
             return json_error_response(
-                "Data could not be retrieved. "
-                "You may want to re-run the query.",
+                'Data could not be retrieved. '
+                'You may want to re-run the query.',
                 status=410,
             )
 
@@ -2065,7 +2065,7 @@ class Superset(BaseSupersetView):
             json.dumps(payload_json, default=utils.json_iso_dttm_ser))
 
     @has_access_api
-    @expose("/stop_query/", methods=['POST'])
+    @expose('/stop_query/', methods=['POST'])
     @log_this
     def stop_query(self):
         client_id = request.form.get('client_id')
@@ -2081,7 +2081,7 @@ class Superset(BaseSupersetView):
         return self.json_response('OK')
 
     @has_access_api
-    @expose("/sql_json/", methods=['POST', 'GET'])
+    @expose('/sql_json/', methods=['POST', 'GET'])
     @log_this
     def sql_json(self):
         """Runs arbitrary sql and returns and json"""
@@ -2130,12 +2130,12 @@ class Superset(BaseSupersetView):
         query_id = query.id
         session.commit()  # shouldn't be necessary
         if not query_id:
-            raise Exception(_("Query record was not created as expected."))
-        logging.info("Triggering query_id: {}".format(query_id))
+            raise Exception(_('Query record was not created as expected.'))
+        logging.info('Triggering query_id: {}'.format(query_id))
 
         # Async request.
         if async:
-            logging.info("Running query on a Celery worker")
+            logging.info('Running query on a Celery worker')
             # Ignore the celery future object and the request may time out.
             try:
                 sql_lab.get_sql_results.delay(
@@ -2144,14 +2144,14 @@ class Superset(BaseSupersetView):
             except Exception as e:
                 logging.exception(e)
                 msg = (
-                    "Failed to start remote query on a worker. "
-                    "Tell your administrator to verify the availability of "
-                    "the message queue."
+                    'Failed to start remote query on a worker. '
+                    'Tell your administrator to verify the availability of '
+                    'the message queue.'
                 )
                 query.status = QueryStatus.FAILED
                 query.error_message = msg
                 session.commit()
-                return json_error_response("{}".format(msg))
+                return json_error_response('{}'.format(msg))
 
             resp = json_success(json.dumps(
                 {'query': query.to_dict()}, default=utils.json_int_dttm_ser,
@@ -2161,10 +2161,10 @@ class Superset(BaseSupersetView):
 
         # Sync request.
         try:
-            timeout = config.get("SQLLAB_TIMEOUT")
+            timeout = config.get('SQLLAB_TIMEOUT')
             timeout_msg = (
-                "The query exceeded the {timeout} seconds "
-                "timeout.").format(**locals())
+                'The query exceeded the {timeout} seconds '
+                'timeout.').format(**locals())
             with utils.timeout(seconds=timeout,
                                error_message=timeout_msg):
                 # pylint: disable=no-value-for-parameter
@@ -2172,17 +2172,17 @@ class Superset(BaseSupersetView):
                     query_id=query_id, return_results=True)
         except Exception as e:
             logging.exception(e)
-            return json_error_response("{}".format(e))
+            return json_error_response('{}'.format(e))
         if data.get('status') == QueryStatus.FAILED:
             return json_error_response(payload=data)
         return json_success(json.dumps(data, default=utils.json_iso_dttm_ser))
 
     @has_access
-    @expose("/csv/<client_id>")
+    @expose('/csv/<client_id>')
     @log_this
     def csv(self, client_id):
         """Download the query results as csv."""
-        logging.info("Exporting CSV file [{}]".format(client_id))
+        logging.info('Exporting CSV file [{}]'.format(client_id))
         query = (
             db.session.query(Query)
             .filter_by(client_id=client_id)
@@ -2197,19 +2197,19 @@ class Superset(BaseSupersetView):
         blob = None
         if results_backend and query.results_key:
             logging.info(
-                "Fetching CSV from results backend "
-                "[{}]".format(query.results_key))
+                'Fetching CSV from results backend '
+                '[{}]'.format(query.results_key))
             blob = results_backend.get(query.results_key)
         if blob:
-            logging.info("Decompressing")
+            logging.info('Decompressing')
             json_payload = utils.zlib_decompress_to_string(blob)
             obj = json.loads(json_payload)
             columns = [c['name'] for c in obj['columns']]
             df = pd.DataFrame.from_records(obj['data'], columns=columns)
-            logging.info("Using pandas to convert to CSV")
+            logging.info('Using pandas to convert to CSV')
             csv = df.to_csv(index=False, **config.get('CSV_EXPORT'))
         else:
-            logging.info("Running a query to turn into CSV")
+            logging.info('Running a query to turn into CSV')
             sql = query.select_sql or query.executed_sql
             df = query.database.get_df(sql, query.schema)
             # TODO(bkyryliuk): add compression=gzip for big files.
@@ -2217,11 +2217,11 @@ class Superset(BaseSupersetView):
         response = Response(csv, mimetype='text/csv')
         response.headers['Content-Disposition'] = (
             'attachment; filename={}.csv'.format(query.name))
-        logging.info("Ready to return response")
+        logging.info('Ready to return response')
         return response
 
     @has_access
-    @expose("/fetch_datasource_metadata")
+    @expose('/fetch_datasource_metadata')
     @log_this
     def fetch_datasource_metadata(self):
         datasource_id, datasource_type = (
@@ -2237,13 +2237,13 @@ class Superset(BaseSupersetView):
             return json_error_response(DATASOURCE_ACCESS_ERR)
         return json_success(json.dumps(datasource.data))
 
-    @expose("/queries/<last_updated_ms>")
+    @expose('/queries/<last_updated_ms>')
     def queries(self, last_updated_ms):
         """Get the updated queries."""
         stats_logger.incr('queries')
         if not g.user.get_id():
             return json_error_response(
-                "Please login to access the queries.", status=403)
+                'Please login to access the queries.', status=403)
 
         # Unix time, milliseconds.
         last_updated_ms_int = int(float(last_updated_ms)) if last_updated_ms else 0
@@ -2264,7 +2264,7 @@ class Superset(BaseSupersetView):
             json.dumps(dict_queries, default=utils.json_int_dttm_ser))
 
     @has_access
-    @expose("/search_queries")
+    @expose('/search_queries')
     @log_this
     def search_queries(self):
         """Search for queries."""
@@ -2312,7 +2312,7 @@ class Superset(BaseSupersetView):
         return Response(
             json.dumps(dict_queries, default=utils.json_int_dttm_ser),
             status=200,
-            mimetype="application/json")
+            mimetype='application/json')
 
     @app.errorhandler(500)
     def show_traceback(self):
@@ -2321,7 +2321,7 @@ class Superset(BaseSupersetView):
             error_msg=get_error_msg(),
         ), 500
 
-    @expose("/welcome")
+    @expose('/welcome')
     def welcome(self):
         """Personalized welcome page"""
         if not g.user or not g.user.get_id():
@@ -2330,7 +2330,7 @@ class Superset(BaseSupersetView):
             'superset/welcome.html', entry='welcome', utils=utils)
 
     @has_access
-    @expose("/profile/<username>/")
+    @expose('/profile/<username>/')
     def profile(self, username):
         """User profile page"""
         if not username and g.user:
@@ -2379,7 +2379,7 @@ class Superset(BaseSupersetView):
         )
 
     @has_access
-    @expose("/sqllab")
+    @expose('/sqllab')
     def sqllab(self):
         """SQL Editor"""
         d = {
@@ -2394,7 +2394,7 @@ class Superset(BaseSupersetView):
 
     @api
     @has_access_api
-    @expose("/slice_query/<slice_id>/")
+    @expose('/slice_query/<slice_id>/')
     def sliceQuery(self, slice_id):
         """
         This method exposes an API endpoint to
@@ -2423,14 +2423,14 @@ class CssTemplateAsyncModelView(CssTemplateModelView):
     list_columns = ['template_name', 'css']
 
 
-appbuilder.add_separator("Sources")
+appbuilder.add_separator('Sources')
 appbuilder.add_view(
     CssTemplateModelView,
-    "CSS Templates",
-    label=__("CSS Templates"),
-    icon="fa-css3",
-    category="Manage",
-    category_label=__("Manage"),
+    'CSS Templates',
+    label=__('CSS Templates'),
+    icon='fa-css3',
+    category='Manage',
+    category_label=__('Manage'),
     category_icon='')
 
 
@@ -2438,22 +2438,22 @@ appbuilder.add_view_no_menu(CssTemplateAsyncModelView)
 
 appbuilder.add_link(
     'SQL Editor',
-    label=_("SQL Editor"),
+    label=_('SQL Editor'),
     href='/superset/sqllab',
-    category_icon="fa-flask",
-    icon="fa-flask",
+    category_icon='fa-flask',
+    icon='fa-flask',
     category='SQL Lab',
-    category_label=__("SQL Lab"),
+    category_label=__('SQL Lab'),
 )
 
 appbuilder.add_link(
     'Query Search',
-    label=_("Query Search"),
+    label=_('Query Search'),
     href='/superset/sqllab#search',
-    icon="fa-search",
-    category_icon="fa-flask",
+    icon='fa-search',
+    category_icon='fa-flask',
     category='SQL Lab',
-    category_label=__("SQL Lab"),
+    category_label=__('SQL Lab'),
 )
 
 
diff --git a/superset/views/sql_lab.py b/superset/views/sql_lab.py
index 06afb4e..488a36e 100644
--- a/superset/views/sql_lab.py
+++ b/superset/views/sql_lab.py
@@ -23,11 +23,11 @@ class QueryView(SupersetModelView):
 
 appbuilder.add_view(
     QueryView,
-    "Queries",
-    label=__("Queries"),
-    category="Manage",
-    category_label=__("Manage"),
-    icon="fa-search")
+    'Queries',
+    label=__('Queries'),
+    category='Manage',
+    category_label=__('Manage'),
+    icon='fa-search')
 
 
 class SavedQueryView(SupersetModelView, DeleteMixin):
@@ -78,13 +78,13 @@ appbuilder.add_view_no_menu(SavedQueryView)
 appbuilder.add_link(
     __('Saved Queries'),
     href='/sqllab/my_queries/',
-    icon="fa-save",
+    icon='fa-save',
     category='SQL Lab')
 
 
 class SqlLab(BaseSupersetView):
     """The base views for Superset!"""
-    @expose("/my_queries/")
+    @expose('/my_queries/')
     def my_queries(self):
         """Assigns a list of found users to the given role."""
         return redirect(
diff --git a/superset/viz.py b/superset/viz.py
index acc90d0..e1ebe74 100644
--- a/superset/viz.py
+++ b/superset/viz.py
@@ -1,4 +1,4 @@
-"""This module contains the "Viz" objects
+"""This module contains the 'Viz' objects
 
 These objects represent the backend of all the visualizations that
 Superset can render.
@@ -41,20 +41,20 @@ class BaseViz(object):
     """All visualizations derive this base class"""
 
     viz_type = None
-    verbose_name = "Base Viz"
-    credits = ""
+    verbose_name = 'Base Viz'
+    credits = ''
     is_timeseries = False
     default_fillna = 0
 
     def __init__(self, datasource, form_data):
         if not datasource:
-            raise Exception(_("Viz is missing a datasource"))
+            raise Exception(_('Viz is missing a datasource'))
         self.datasource = datasource
         self.request = request
-        self.viz_type = form_data.get("viz_type")
+        self.viz_type = form_data.get('viz_type')
         self.form_data = form_data
 
-        self.query = ""
+        self.query = ''
         self.token = self.form_data.get(
             'token', 'token_' + uuid.uuid4().hex[:8])
         self.metrics = self.form_data.get('metrics') or []
@@ -84,7 +84,7 @@ class BaseViz(object):
         if not query_obj:
             query_obj = self.query_obj()
 
-        self.error_msg = ""
+        self.error_msg = ''
         self.results = None
 
         timestamp_format = None
@@ -108,11 +108,11 @@ class BaseViz(object):
         if df is None or df.empty:
             self.status = utils.QueryStatus.FAILED
             if not self.error_message:
-                self.error_message = "No data."
+                self.error_message = 'No data.'
             return pd.DataFrame()
         else:
             if DTTM_ALIAS in df.columns:
-                if timestamp_format in ("epoch_s", "epoch_ms"):
+                if timestamp_format in ('epoch_s', 'epoch_ms'):
                     df[DTTM_ALIAS] = pd.to_datetime(df[DTTM_ALIAS], utc=False)
                 else:
                     df[DTTM_ALIAS] = pd.to_datetime(
@@ -127,9 +127,9 @@ class BaseViz(object):
     def query_obj(self):
         """Building a query object"""
         form_data = self.form_data
-        gb = form_data.get("groupby") or []
-        metrics = form_data.get("metrics") or []
-        columns = form_data.get("columns") or []
+        gb = form_data.get('groupby') or []
+        metrics = form_data.get('metrics') or []
+        columns = form_data.get('columns') or []
         groupby = []
         for o in gb + columns:
             if o not in groupby:
@@ -144,18 +144,18 @@ class BaseViz(object):
         merge_extra_filters(form_data)
 
         granularity = (
-            form_data.get("granularity") or
-            form_data.get("granularity_sqla")
+            form_data.get('granularity') or
+            form_data.get('granularity_sqla')
         )
-        limit = int(form_data.get("limit") or 0)
-        timeseries_limit_metric = form_data.get("timeseries_limit_metric")
-        row_limit = int(form_data.get("row_limit") or config.get("ROW_LIMIT"))
+        limit = int(form_data.get('limit') or 0)
+        timeseries_limit_metric = form_data.get('timeseries_limit_metric')
+        row_limit = int(form_data.get('row_limit') or config.get('ROW_LIMIT'))
 
         # default order direction
-        order_desc = form_data.get("order_desc", True)
+        order_desc = form_data.get('order_desc', True)
 
-        since = form_data.get("since", "")
-        until = form_data.get("until", "now")
+        since = form_data.get('since', '')
+        until = form_data.get('until', 'now')
 
         # Backward compatibility hack
         if since:
@@ -168,20 +168,20 @@ class BaseViz(object):
 
         to_dttm = utils.parse_human_datetime(until)
         if from_dttm and to_dttm and from_dttm > to_dttm:
-            raise Exception(_("From date cannot be larger than to date"))
+            raise Exception(_('From date cannot be larger than to date'))
 
         self.from_dttm = from_dttm
         self.to_dttm = to_dttm
-        self.annotation_layers = form_data.get("annotation_layers") or []
+        self.annotation_layers = form_data.get('annotation_layers') or []
 
         # extras are used to query elements specific to a datasource type
         # for instance the extra where clause that applies only to Tables
         extras = {
-            'where': form_data.get("where", ''),
-            'having': form_data.get("having", ''),
+            'where': form_data.get('where', ''),
+            'having': form_data.get('having', ''),
             'having_druid': form_data.get('having_filters', []),
-            'time_grain_sqla': form_data.get("time_grain_sqla", ''),
-            'druid_time_origin': form_data.get("druid_time_origin", ''),
+            'time_grain_sqla': form_data.get('time_grain_sqla', ''),
+            'druid_time_origin': form_data.get('druid_time_origin', ''),
         }
         filters = form_data.get('filters', [])
         d = {
@@ -211,7 +211,7 @@ class BaseViz(object):
                 hasattr(self.datasource, 'database') and
                 self.datasource.database.cache_timeout):
             return self.datasource.database.cache_timeout
-        return config.get("CACHE_DEFAULT_TIMEOUT")
+        return config.get('CACHE_DEFAULT_TIMEOUT')
 
     def get_json(self, force=False):
         return json.dumps(
@@ -256,11 +256,11 @@ class BaseViz(object):
                     cached_data = cached_data.decode('utf-8')
                 payload = json.loads(cached_data)
             except Exception as e:
-                logging.error("Error reading cache: " +
+                logging.error('Error reading cache: ' +
                               utils.error_msg_from_exception(e))
                 payload = None
                 return []
-            logging.info("Serving from cache")
+            logging.info('Serving from cache')
 
         if not payload:
             stats_logger.incr('loaded_from_source')
@@ -293,7 +293,7 @@ class BaseViz(object):
                 'annotations': annotations,
             }
             payload['cached_dttm'] = datetime.utcnow().isoformat().split('.')[0]
-            logging.info("Caching for the next {} seconds".format(
+            logging.info('Caching for the next {} seconds'.format(
                 cache_timeout))
             data = self.json_dumps(payload)
             if PY3:
@@ -307,7 +307,7 @@ class BaseViz(object):
                 except Exception as e:
                     # cache.set call can fail if the backend is down or if
                     # the key is too large or whatever other reasons
-                    logging.warning("Could not cache key {}".format(cache_key))
+                    logging.warning('Could not cache key {}'.format(cache_key))
                     logging.exception(e)
                     cache.delete(cache_key)
         payload['is_cached'] = is_cached
@@ -344,8 +344,8 @@ class TableViz(BaseViz):
 
     """A basic html table that is sortable and searchable"""
 
-    viz_type = "table"
-    verbose_name = _("Table View")
+    viz_type = 'table'
+    verbose_name = _('Table View')
     credits = 'a <a href="https://github.com/airbnb/superset">Superset</a> original'
     is_timeseries = False
 
@@ -358,7 +358,7 @@ class TableViz(BaseViz):
         )
         if fd.get('include_time') and not conditions_met:
             raise Exception(_(
-                "Pick a granularity in the Time section or "
+                'Pick a granularity in the Time section or '
                 "uncheck 'Include Time'"))
         return fd.get('include_time')
 
@@ -368,8 +368,8 @@ class TableViz(BaseViz):
 
         if fd.get('all_columns') and (fd.get('groupby') or fd.get('metrics')):
             raise Exception(_(
-                "Choose either fields to [Group By] and [Metrics] or "
-                "[Columns], not both"))
+                'Choose either fields to [Group By] and [Metrics] or '
+                '[Columns], not both'))
 
         sort_by = fd.get('timeseries_limit_metric')
         if fd.get('all_columns'):
@@ -380,7 +380,7 @@ class TableViz(BaseViz):
         elif sort_by:
             if sort_by not in d['metrics']:
                 d['metrics'] += [sort_by]
-            d['orderby'] = [(sort_by, not fd.get("order_desc", True))]
+            d['orderby'] = [(sort_by, not fd.get('order_desc', True))]
 
         # Add all percent metrics that are not already in the list
         if 'percent_metrics' in fd:
@@ -420,7 +420,7 @@ class TableViz(BaseViz):
                 del df[m]
 
         return dict(
-            records=df.to_dict(orient="records"),
+            records=df.to_dict(orient='records'),
             columns=list(df.columns),
         )
 
@@ -435,8 +435,8 @@ class TimeTableViz(BaseViz):
 
     """A data table with rich time-series related columns"""
 
-    viz_type = "time_table"
-    verbose_name = _("Time Table View")
+    viz_type = 'time_table'
+    verbose_name = _('Time Table View')
     credits = 'a <a href="https://github.com/airbnb/superset">Superset</a> original'
     is_timeseries = True
 
@@ -445,12 +445,11 @@ class TimeTableViz(BaseViz):
         fd = self.form_data
 
         if not fd.get('metrics'):
-            raise Exception(_("Pick at least one metric"))
+            raise Exception(_('Pick at least one metric'))
 
         if fd.get('groupby') and len(fd.get('metrics')) > 1:
             raise Exception(_(
-                "When using 'Group By' you are limited to use "
-                "a single metric"))
+                "When using 'Group By' you are limited to use a single metric"))
         return d
 
     def get_data(self, df):
@@ -477,8 +476,8 @@ class PivotTableViz(BaseViz):
 
     """A pivot table view, define your rows, columns and metrics"""
 
-    viz_type = "pivot_table"
-    verbose_name = _("Pivot Table")
+    viz_type = 'pivot_table'
+    verbose_name = _('Pivot Table')
     credits = 'a <a href="https://github.com/airbnb/superset">Superset</a> original'
     is_timeseries = False
 
@@ -492,18 +491,18 @@ class PivotTableViz(BaseViz):
         if not groupby:
             groupby = []
         if not groupby:
-            raise Exception(_("Please choose at least one \"Group by\" field "))
+            raise Exception(_("Please choose at least one 'Group by' field "))
         if not metrics:
-            raise Exception(_("Please choose at least one metric"))
+            raise Exception(_('Please choose at least one metric'))
         if (
                 any(v in groupby for v in columns) or
                 any(v in columns for v in groupby)):
-            raise Exception(_("'Group By' and 'Columns' can't overlap"))
+            raise Exception(_("Group By' and 'Columns' can't overlap"))
         return d
 
     def get_data(self, df):
         if (
-                self.form_data.get("granularity") == "all" and
+                self.form_data.get('granularity') == 'all' and
                 DTTM_ALIAS in df):
             del df[DTTM_ALIAS]
         df = df.pivot_table(
@@ -521,8 +520,8 @@ class PivotTableViz(BaseViz):
             html=df.to_html(
                 na_rep='',
                 classes=(
-                    "dataframe table table-striped table-bordered "
-                    "table-condensed table-hover").split(" ")),
+                    'dataframe table table-striped table-bordered '
+                    'table-condensed table-hover').split(' ')),
         )
 
 
@@ -530,17 +529,17 @@ class MarkupViz(BaseViz):
 
     """Use html or markdown to create a free form widget"""
 
-    viz_type = "markup"
-    verbose_name = _("Markup")
+    viz_type = 'markup'
+    verbose_name = _('Markup')
     is_timeseries = False
 
     def get_df(self):
         return True
 
     def get_data(self, df):
-        markup_type = self.form_data.get("markup_type")
-        code = self.form_data.get("code", '')
-        if markup_type == "markdown":
+        markup_type = self.form_data.get('markup_type')
+        code = self.form_data.get('code', '')
+        if markup_type == 'markdown':
             code = markdown(code)
         return dict(html=code, theme_css=get_manifest_file('theme.css'))
 
@@ -549,8 +548,8 @@ class SeparatorViz(MarkupViz):
 
     """Use to create section headers in a dashboard, similar to `Markup`"""
 
-    viz_type = "separator"
-    verbose_name = _("Separator")
+    viz_type = 'separator'
+    verbose_name = _('Separator')
 
 
 class WordCloudViz(BaseViz):
@@ -561,8 +560,8 @@ class WordCloudViz(BaseViz):
     https://github.com/jasondavies/d3-cloud
     """
 
-    viz_type = "word_cloud"
-    verbose_name = _("Word Cloud")
+    viz_type = 'word_cloud'
+    verbose_name = _('Word Cloud')
     is_timeseries = False
 
     def query_obj(self):
@@ -577,31 +576,31 @@ class WordCloudViz(BaseViz):
         df = df[[self.form_data.get('series'), self.form_data.get('metric')]]
         # Labeling the columns for uniform json schema
         df.columns = ['text', 'size']
-        return df.to_dict(orient="records")
+        return df.to_dict(orient='records')
 
 
 class TreemapViz(BaseViz):
 
     """Tree map visualisation for hierarchical data."""
 
-    viz_type = "treemap"
-    verbose_name = _("Treemap")
+    viz_type = 'treemap'
+    verbose_name = _('Treemap')
     credits = '<a href="https://d3js.org">d3.js</a>'
     is_timeseries = False
 
     def _nest(self, metric, df):
         nlevels = df.index.nlevels
         if nlevels == 1:
-            result = [{"name": n, "value": v}
+            result = [{'name': n, 'value': v}
                       for n, v in zip(df.index, df[metric])]
         else:
-            result = [{"name": l, "children": self._nest(metric, df.loc[l])}
+            result = [{'name': l, 'children': self._nest(metric, df.loc[l])}
                       for l in df.index.levels[0]]
         return result
 
     def get_data(self, df):
-        df = df.set_index(self.form_data.get("groupby"))
-        chart_data = [{"name": metric, "children": self._nest(metric, df)}
+        df = df.set_index(self.form_data.get('groupby'))
+        chart_data = [{'name': metric, 'children': self._nest(metric, df)}
                       for metric in df.columns]
         return chart_data
 
@@ -610,8 +609,8 @@ class CalHeatmapViz(BaseViz):
 
     """Calendar heatmap."""
 
-    viz_type = "cal_heatmap"
-    verbose_name = _("Calendar Heatmap")
+    viz_type = 'cal_heatmap'
+    verbose_name = _('Calendar Heatmap')
     credits = (
         '<a href=https://github.com/wa0x6e/cal-heatmap>cal-heatmap</a>')
     is_timeseries = True
@@ -619,38 +618,38 @@ class CalHeatmapViz(BaseViz):
     def get_data(self, df):
         form_data = self.form_data
 
-        df.columns = ["timestamp", "metric"]
-        timestamps = {str(obj["timestamp"].value / 10**9):
-                      obj.get("metric") for obj in df.to_dict("records")}
+        df.columns = ['timestamp', 'metric']
+        timestamps = {str(obj['timestamp'].value / 10**9):
+                      obj.get('metric') for obj in df.to_dict('records')}
 
-        start = utils.parse_human_datetime(form_data.get("since"))
-        end = utils.parse_human_datetime(form_data.get("until"))
-        domain = form_data.get("domain_granularity")
+        start = utils.parse_human_datetime(form_data.get('since'))
+        end = utils.parse_human_datetime(form_data.get('until'))
+        domain = form_data.get('domain_granularity')
         diff_delta = rdelta.relativedelta(end, start)
         diff_secs = (end - start).total_seconds()
 
-        if domain == "year":
+        if domain == 'year':
             range_ = diff_delta.years + 1
-        elif domain == "month":
+        elif domain == 'month':
             range_ = diff_delta.years * 12 + diff_delta.months + 1
-        elif domain == "week":
+        elif domain == 'week':
             range_ = diff_delta.years * 53 + diff_delta.weeks + 1
-        elif domain == "day":
+        elif domain == 'day':
             range_ = diff_secs // (24 * 60 * 60) + 1
         else:
             range_ = diff_secs // (60 * 60) + 1
 
         return {
-            "timestamps": timestamps,
-            "start": start,
-            "domain": domain,
-            "subdomain": form_data.get("subdomain_granularity"),
-            "range": range_,
+            'timestamps': timestamps,
+            'start': start,
+            'domain': domain,
+            'subdomain': form_data.get('subdomain_granularity'),
+            'range': range_,
         }
 
     def query_obj(self):
         qry = super(CalHeatmapViz, self).query_obj()
-        qry["metrics"] = [self.form_data["metric"]]
+        qry['metrics'] = [self.form_data['metric']]
         return qry
 
 
@@ -660,7 +659,7 @@ class NVD3Viz(BaseViz):
 
     credits = '<a href="http://nvd3.org/">NVD3.org</a>'
     viz_type = None
-    verbose_name = "Base NVD3 Viz"
+    verbose_name = 'Base NVD3 Viz'
     is_timeseries = False
 
 
@@ -668,31 +667,31 @@ class BoxPlotViz(NVD3Viz):
 
     """Box plot viz from ND3"""
 
-    viz_type = "box_plot"
-    verbose_name = _("Box Plot")
+    viz_type = 'box_plot'
+    verbose_name = _('Box Plot')
     sort_series = False
     is_timeseries = True
 
     def to_series(self, df, classed='', title_suffix=''):
-        label_sep = " - "
+        label_sep = ' - '
         chart_data = []
-        for index_value, row in zip(df.index, df.to_dict(orient="records")):
+        for index_value, row in zip(df.index, df.to_dict(orient='records')):
             if isinstance(index_value, tuple):
                 index_value = label_sep.join(index_value)
             boxes = defaultdict(dict)
             for (label, key), value in row.items():
-                if key == "median":
-                    key = "Q2"
+                if key == 'median':
+                    key = 'Q2'
                 boxes[label][key] = value
             for label, box in boxes.items():
-                if len(self.form_data.get("metrics")) > 1:
+                if len(self.form_data.get('metrics')) > 1:
                     # need to render data labels with metrics
                     chart_label = label_sep.join([index_value, label])
                 else:
                     chart_label = index_value
                 chart_data.append({
-                    "label": chart_label,
-                    "values": box,
+                    'label': chart_label,
+                    'values': box,
                 })
         return chart_data
 
@@ -708,7 +707,7 @@ class BoxPlotViz(NVD3Viz):
             return np.percentile(series, 75)
 
         whisker_type = form_data.get('whisker_options')
-        if whisker_type == "Tukey":
+        if whisker_type == 'Tukey':
 
             def whisker_high(series):
                 upper_outer_lim = Q3(series) + 1.5 * (Q3(series) - Q1(series))
@@ -721,7 +720,7 @@ class BoxPlotViz(NVD3Viz):
                 series = series[series >= lower_outer_lim]
                 return series[np.abs(series - lower_outer_lim).argmin()]
 
-        elif whisker_type == "Min/max (no outliers)":
+        elif whisker_type == 'Min/max (no outliers)':
 
             def whisker_high(series):
                 return series.max()
@@ -729,8 +728,8 @@ class BoxPlotViz(NVD3Viz):
             def whisker_low(series):
                 return series.min()
 
-        elif " percentiles" in whisker_type:
-            low, high = whisker_type.replace(" percentiles", "").split("/")
+        elif ' percentiles' in whisker_type:
+            low, high = whisker_type.replace(' percentiles', '').split('/')
 
             def whisker_high(series):
                 return np.percentile(series, int(high))
@@ -739,7 +738,7 @@ class BoxPlotViz(NVD3Viz):
                 return np.percentile(series, int(low))
 
         else:
-            raise ValueError("Unknown whisker type: {}".format(whisker_type))
+            raise ValueError('Unknown whisker type: {}'.format(whisker_type))
 
         def outliers(series):
             above = series[series > whisker_high(series)]
@@ -757,8 +756,8 @@ class BubbleViz(NVD3Viz):
 
     """Based on the NVD3 bubble chart"""
 
-    viz_type = "bubble"
-    verbose_name = _("Bubble Chart")
+    viz_type = 'bubble'
+    verbose_name = _('Bubble Chart')
     is_timeseries = False
 
     def query_obj(self):
@@ -782,7 +781,7 @@ class BubbleViz(NVD3Viz):
             self.y_metric,
         ]
         if not all(d['metrics'] + [self.entity]):
-            raise Exception(_("Pick a metric for x, y and size"))
+            raise Exception(_('Pick a metric for x, y and size'))
         return d
 
     def get_data(self, df):
@@ -807,8 +806,8 @@ class BulletViz(NVD3Viz):
 
     """Based on the NVD3 bullet chart"""
 
-    viz_type = "bullet"
-    verbose_name = _("Bullet Chart")
+    viz_type = 'bullet'
+    verbose_name = _('Bullet Chart')
     is_timeseries = False
 
     def query_obj(self):
@@ -834,7 +833,7 @@ class BulletViz(NVD3Viz):
             self.metric,
         ]
         if not self.metric:
-            raise Exception(_("Pick a metric to display"))
+            raise Exception(_('Pick a metric to display'))
         return d
 
     def get_data(self, df):
@@ -856,8 +855,8 @@ class BigNumberViz(BaseViz):
 
     """Put emphasis on a single metric with this big number viz"""
 
-    viz_type = "big_number"
-    verbose_name = _("Big Number with Trendline")
+    viz_type = 'big_number'
+    verbose_name = _('Big Number with Trendline')
     credits = 'a <a href="https://github.com/airbnb/superset">Superset</a> original'
     is_timeseries = True
 
@@ -865,7 +864,7 @@ class BigNumberViz(BaseViz):
         d = super(BigNumberViz, self).query_obj()
         metric = self.form_data.get('metric')
         if not metric:
-            raise Exception(_("Pick a metric!"))
+            raise Exception(_('Pick a metric!'))
         d['metrics'] = [self.form_data.get('metric')]
         self.form_data['metric'] = metric
         return d
@@ -873,7 +872,7 @@ class BigNumberViz(BaseViz):
     def get_data(self, df):
         form_data = self.form_data
         df.sort_values(by=df.columns[0], inplace=True)
-        compare_lag = form_data.get("compare_lag")
+        compare_lag = form_data.get('compare_lag')
         return {
             'data': df.values.tolist(),
             'compare_lag': compare_lag,
@@ -885,8 +884,8 @@ class BigNumberTotalViz(BaseViz):
 
     """Put emphasis on a single metric with this big number viz"""
 
-    viz_type = "big_number_total"
-    verbose_name = _("Big Number")
+    viz_type = 'big_number_total'
+    verbose_name = _('Big Number')
     credits = 'a <a href="https://github.com/airbnb/superset">Superset</a> original'
     is_timeseries = False
 
@@ -894,7 +893,7 @@ class BigNumberTotalViz(BaseViz):
         d = super(BigNumberTotalViz, self).query_obj()
         metric = self.form_data.get('metric')
         if not metric:
-            raise Exception(_("Pick a metric!"))
+            raise Exception(_('Pick a metric!'))
         d['metrics'] = [self.form_data.get('metric')]
         self.form_data['metric'] = metric
         return d
@@ -912,8 +911,8 @@ class NVD3TimeSeriesViz(NVD3Viz):
 
     """A rich line chart component with tons of options"""
 
-    viz_type = "line"
-    verbose_name = _("Time Series - Line Chart")
+    viz_type = 'line'
+    verbose_name = _('Time Series - Line Chart')
     sort_series = False
     is_timeseries = True
 
@@ -932,7 +931,7 @@ class NVD3TimeSeriesViz(NVD3Viz):
         chart_data = []
         for name in df.T.index.tolist():
             ys = series[name]
-            if df[name].dtype.kind not in "biufc":
+            if df[name].dtype.kind not in 'biufc':
                 continue
             series_title = name
             if (
@@ -947,9 +946,9 @@ class NVD3TimeSeriesViz(NVD3Viz):
                 series_title = series_title + (title_suffix,)
 
             d = {
-                "key": series_title,
-                "classed": classed,
-                "values": [
+                'key': series_title,
+                'classed': classed,
+                'values': [
                     {'x': ds, 'y': ys[ds] if ds in ys else None}
                     for ds in df.index
                 ],
@@ -960,8 +959,8 @@ class NVD3TimeSeriesViz(NVD3Viz):
     def process_data(self, df, aggregate=False):
         fd = self.form_data
         df = df.fillna(0)
-        if fd.get("granularity") == "all":
-            raise Exception(_("Pick a time granularity for your time series"))
+        if fd.get('granularity') == 'all':
+            raise Exception(_('Pick a time granularity for your time series'))
 
         if not aggregate:
             df = df.pivot_table(
@@ -976,11 +975,11 @@ class NVD3TimeSeriesViz(NVD3Viz):
                 fill_value=0,
                 aggfunc=sum)
 
-        fm = fd.get("resample_fillmethod")
+        fm = fd.get('resample_fillmethod')
         if not fm:
             fm = None
-        how = fd.get("resample_how")
-        rule = fd.get("resample_rule")
+        how = fd.get('resample_how')
+        rule = fd.get('resample_rule')
         if how and rule:
             df = df.resample(rule, how=how, fill_method=fm)
             if not fm:
@@ -991,13 +990,13 @@ class NVD3TimeSeriesViz(NVD3Viz):
             dfs.sort_values(ascending=False, inplace=True)
             df = df[dfs.index]
 
-        if fd.get("contribution"):
+        if fd.get('contribution'):
             dft = df.T
             df = (dft / dft.sum()).T
 
-        rolling_type = fd.get("rolling_type")
-        rolling_periods = int(fd.get("rolling_periods") or 0)
-        min_periods = int(fd.get("min_periods") or 0)
+        rolling_type = fd.get('rolling_type')
+        rolling_periods = int(fd.get('rolling_periods') or 0)
+        min_periods = int(fd.get('min_periods') or 0)
 
         if rolling_type in ('mean', 'std', 'sum') and rolling_periods:
             kwargs = dict(
@@ -1015,7 +1014,7 @@ class NVD3TimeSeriesViz(NVD3Viz):
         if min_periods:
             df = df[min_periods:]
 
-        num_period_compare = fd.get("num_period_compare")
+        num_period_compare = fd.get('num_period_compare')
         if num_period_compare:
             num_period_compare = int(num_period_compare)
             prt = fd.get('period_ratio_type')
@@ -1047,7 +1046,7 @@ class NVD3TimeSeriesViz(NVD3Viz):
             df2[DTTM_ALIAS] += delta
             df2 = self.process_data(df2)
             chart_data += self.to_series(
-                df2, classed='superset', title_suffix="---")
+                df2, classed='superset', title_suffix='---')
             chart_data = sorted(chart_data, key=lambda x: x['key'])
         return chart_data
 
@@ -1056,8 +1055,8 @@ class NVD3DualLineViz(NVD3Viz):
 
     """A rich line chart with dual axis"""
 
-    viz_type = "dual_line"
-    verbose_name = _("Time Series - Dual Axis Line Chart")
+    viz_type = 'dual_line'
+    verbose_name = _('Time Series - Dual Axis Line Chart')
     sort_series = False
     is_timeseries = True
 
@@ -1067,12 +1066,12 @@ class NVD3DualLineViz(NVD3Viz):
         m2 = self.form_data.get('metric_2')
         d['metrics'] = [m1, m2]
         if not m1:
-            raise Exception(_("Pick a metric for left axis!"))
+            raise Exception(_('Pick a metric for left axis!'))
         if not m2:
-            raise Exception(_("Pick a metric for right axis!"))
+            raise Exception(_('Pick a metric for right axis!'))
         if m1 == m2:
-            raise Exception(_("Please choose different metrics"
-                            " on left and right axis"))
+            raise Exception(_('Please choose different metrics'
+                            ' on left and right axis'))
         return d
 
     def to_series(self, df, classed=''):
@@ -1093,18 +1092,18 @@ class NVD3DualLineViz(NVD3Viz):
         ]
         for i, m in enumerate(metrics):
             ys = series[m]
-            if df[m].dtype.kind not in "biufc":
+            if df[m].dtype.kind not in 'biufc':
                 continue
             series_title = m
             d = {
-                "key": series_title,
-                "classed": classed,
-                "values": [
+                'key': series_title,
+                'classed': classed,
+                'values': [
                     {'x': ds, 'y': ys[ds] if ds in ys else None}
                     for ds in df.index
                 ],
-                "yAxis": i + 1,
-                "type": "line",
+                'yAxis': i + 1,
+                'type': 'line',
             }
             chart_data.append(d)
         return chart_data
@@ -1113,8 +1112,8 @@ class NVD3DualLineViz(NVD3Viz):
         fd = self.form_data
         df = df.fillna(0)
 
-        if self.form_data.get("granularity") == "all":
-            raise Exception(_("Pick a time granularity for your time series"))
+        if self.form_data.get('granularity') == 'all':
+            raise Exception(_('Pick a time granularity for your time series'))
 
         metric = fd.get('metric')
         metric_2 = fd.get('metric_2')
@@ -1130,9 +1129,9 @@ class NVD3TimeSeriesBarViz(NVD3TimeSeriesViz):
 
     """A bar chart where the x axis is time"""
 
-    viz_type = "bar"
+    viz_type = 'bar'
     sort_series = True
-    verbose_name = _("Time Series - Bar Chart")
+    verbose_name = _('Time Series - Bar Chart')
 
 
 class NVD3CompareTimeSeriesViz(NVD3TimeSeriesViz):
@@ -1140,15 +1139,15 @@ class NVD3CompareTimeSeriesViz(NVD3TimeSeriesViz):
     """A line chart component where you can compare the % change over time"""
 
     viz_type = 'compare'
-    verbose_name = _("Time Series - Percent Change")
+    verbose_name = _('Time Series - Percent Change')
 
 
 class NVD3TimeSeriesStackedViz(NVD3TimeSeriesViz):
 
     """A rich stack area chart"""
 
-    viz_type = "area"
-    verbose_name = _("Time Series - Stacked")
+    viz_type = 'area'
+    verbose_name = _('Time Series - Stacked')
     sort_series = True
 
 
@@ -1156,8 +1155,8 @@ class DistributionPieViz(NVD3Viz):
 
     """Annoy visualization snobs with this controversial pie chart"""
 
-    viz_type = "pie"
-    verbose_name = _("Distribution - NVD3 - Pie Chart")
+    viz_type = 'pie'
+    verbose_name = _('Distribution - NVD3 - Pie Chart')
     is_timeseries = False
 
     def get_data(self, df):
@@ -1167,15 +1166,15 @@ class DistributionPieViz(NVD3Viz):
         df.sort_values(by=self.metrics[0], ascending=False, inplace=True)
         df = df.reset_index()
         df.columns = ['x', 'y']
-        return df.to_dict(orient="records")
+        return df.to_dict(orient='records')
 
 
 class HistogramViz(BaseViz):
 
     """Histogram"""
 
-    viz_type = "histogram"
-    verbose_name = _("Histogram")
+    viz_type = 'histogram'
+    verbose_name = _('Histogram')
     is_timeseries = False
 
     def query_obj(self):
@@ -1185,7 +1184,7 @@ class HistogramViz(BaseViz):
             'row_limit', int(config.get('VIZ_ROW_LIMIT')))
         numeric_column = self.form_data.get('all_columns_x')
         if numeric_column is None:
-            raise Exception(_("Must have one numeric column specified"))
+            raise Exception(_('Must have one numeric column specified'))
         d['columns'] = [numeric_column]
         return d
 
@@ -1199,8 +1198,8 @@ class DistributionBarViz(DistributionPieViz):
 
     """A good old bar chart"""
 
-    viz_type = "dist_bar"
-    verbose_name = _("Distribution - Bar Chart")
+    viz_type = 'dist_bar'
+    verbose_name = _('Distribution - Bar Chart')
     is_timeseries = False
 
     def query_obj(self):
@@ -1213,9 +1212,9 @@ class DistributionBarViz(DistributionPieViz):
             raise Exception(
                 _("Can't have overlap between Series and Breakdowns"))
         if not fd.get('metrics'):
-            raise Exception(_("Pick at least one metric"))
+            raise Exception(_('Pick at least one metric'))
         if not fd.get('groupby'):
-            raise Exception(_("Pick at least one field for [Series]"))
+            raise Exception(_('Pick at least one field for [Series]'))
         return d
 
     def get_data(self, df):
@@ -1228,22 +1227,22 @@ class DistributionBarViz(DistributionPieViz):
             index=self.groupby,
             columns=columns,
             values=self.metrics)
-        if fd.get("contribution"):
+        if fd.get('contribution'):
             pt = pt.fillna(0)
             pt = pt.T
             pt = (pt / pt.sum()).T
         pt = pt.reindex(row.index)
         chart_data = []
         for name, ys in pt.iteritems():
-            if pt[name].dtype.kind not in "biufc" or name in self.groupby:
+            if pt[name].dtype.kind not in 'biufc' or name in self.groupby:
                 continue
             if isinstance(name, string_types):
                 series_title = name
             elif len(self.metrics) > 1:
-                series_title = ", ".join(name)
+                series_title = ', '.join(name)
             else:
                 l = [str(s) for s in name[1:]]  # noqa: E741
-                series_title = ", ".join(l)
+                series_title = ', '.join(l)
             values = []
             for i, v in ys.iteritems():
                 x = i
@@ -1256,8 +1255,8 @@ class DistributionBarViz(DistributionPieViz):
                     'y': v,
                 })
             d = {
-                "key": series_title,
-                "values": values,
+                'key': series_title,
+                'values': values,
             }
             chart_data.append(d)
         return chart_data
@@ -1267,8 +1266,8 @@ class SunburstViz(BaseViz):
 
     """A multi level sunburst chart"""
 
-    viz_type = "sunburst"
-    verbose_name = _("Sunburst")
+    viz_type = 'sunburst'
+    verbose_name = _('Sunburst')
     is_timeseries = False
     credits = (
         'Kerry Rodden '
@@ -1287,7 +1286,7 @@ class SunburstViz(BaseViz):
             cols += [
                 self.form_data['metric'], self.form_data['secondary_metric']]
             ndf = df[cols]
-        return json.loads(ndf.to_json(orient="values"))  # TODO fix this nonsense
+        return json.loads(ndf.to_json(orient='values'))  # TODO fix this nonsense
 
     def query_obj(self):
         qry = super(SunburstViz, self).query_obj()
@@ -1300,15 +1299,15 @@ class SankeyViz(BaseViz):
 
     """A Sankey diagram that requires a parent-child dataset"""
 
-    viz_type = "sankey"
-    verbose_name = _("Sankey")
+    viz_type = 'sankey'
+    verbose_name = _('Sankey')
     is_timeseries = False
     credits = '<a href="https://www.npmjs.com/package/d3-sankey">d3-sankey on npm</a>'
 
     def query_obj(self):
         qry = super(SankeyViz, self).query_obj()
         if len(qry['groupby']) != 2:
-            raise Exception(_("Pick exactly 2 columns as [Source / Target]"))
+            raise Exception(_('Pick exactly 2 columns as [Source / Target]'))
         qry['metrics'] = [
             self.form_data['metric']]
         return qry
@@ -1349,8 +1348,8 @@ class DirectedForceViz(BaseViz):
 
     """An animated directed force layout graph visualization"""
 
-    viz_type = "directed_force"
-    verbose_name = _("Directed Force Layout")
+    viz_type = 'directed_force'
+    verbose_name = _('Directed Force Layout')
     credits = 'd3noob @<a href="http://bl.ocks.org/d3noob/5141278">bl.ocks.org</a>'
     is_timeseries = False
 
@@ -1370,8 +1369,8 @@ class ChordViz(BaseViz):
 
     """A Chord diagram"""
 
-    viz_type = "chord"
-    verbose_name = _("Directed Force Layout")
+    viz_type = 'chord'
+    verbose_name = _('Directed Force Layout')
     credits = '<a href="https://github.com/d3/d3-chord">Bostock</a>'
     is_timeseries = False
 
@@ -1403,8 +1402,8 @@ class CountryMapViz(BaseViz):
 
     """A country centric"""
 
-    viz_type = "country_map"
-    verbose_name = _("Country Map")
+    viz_type = 'country_map'
+    verbose_name = _('Country Map')
     is_timeseries = False
     credits = 'From bl.ocks.org By john-guerra'
 
@@ -1431,8 +1430,8 @@ class WorldMapViz(BaseViz):
 
     """A country centric world map"""
 
-    viz_type = "world_map"
-    verbose_name = _("World Map")
+    viz_type = 'world_map'
+    verbose_name = _('World Map')
     is_timeseries = False
     credits = 'datamaps on <a href="https://www.npmjs.com/package/datamaps">npm</a>'
 
@@ -1473,7 +1472,7 @@ class WorldMapViz(BaseViz):
                 row['longitude'] = country['lng']
                 row['name'] = country['name']
             else:
-                row['country'] = "XXX"
+                row['country'] = 'XXX'
         return d
 
 
@@ -1481,8 +1480,8 @@ class FilterBoxViz(BaseViz):
 
     """A multi filter, multi-choice filter box to make dashboards interactive"""
 
-    viz_type = "filter_box"
-    verbose_name = _("Filters")
+    viz_type = 'filter_box'
+    verbose_name = _('Filters')
     is_timeseries = False
     credits = 'a <a href="https://github.com/airbnb/superset">Superset</a> original'
 
@@ -1490,7 +1489,7 @@ class FilterBoxViz(BaseViz):
         qry = super(FilterBoxViz, self).query_obj()
         groupby = self.form_data.get('groupby')
         if len(groupby) < 1 and not self.form_data.get('date_filter'):
-            raise Exception(_("Pick at least one filter field"))
+            raise Exception(_('Pick at least one filter field'))
         qry['metrics'] = [
             self.form_data['metric']]
         return qry
@@ -1516,8 +1515,8 @@ class IFrameViz(BaseViz):
 
     """You can squeeze just about anything in this iFrame component"""
 
-    viz_type = "iframe"
-    verbose_name = _("iFrame")
+    viz_type = 'iframe'
+    verbose_name = _('iFrame')
     credits = 'a <a href="https://github.com/airbnb/superset">Superset</a> original'
     is_timeseries = False
 
@@ -1533,11 +1532,11 @@ class ParallelCoordinatesViz(BaseViz):
     https://github.com/syntagmatic/parallel-coordinates
     """
 
-    viz_type = "para"
-    verbose_name = _("Parallel Coordinates")
+    viz_type = 'para'
+    verbose_name = _('Parallel Coordinates')
     credits = (
         '<a href="https://syntagmatic.github.io/parallel-coordinates/">'
-        'Syntagmatic\'s library</a>')
+        "Syntagmatic's library</a>")
     is_timeseries = False
 
     def query_obj(self):
@@ -1551,15 +1550,15 @@ class ParallelCoordinatesViz(BaseViz):
         return d
 
     def get_data(self, df):
-        return df.to_dict(orient="records")
+        return df.to_dict(orient='records')
 
 
 class HeatmapViz(BaseViz):
 
     """A nice heatmap visualization that support high density through canvas"""
 
-    viz_type = "heatmap"
-    verbose_name = _("Heatmap")
+    viz_type = 'heatmap'
+    verbose_name = _('Heatmap')
     is_timeseries = False
     credits = (
         'inspired from mbostock @<a href="http://bl.ocks.org/mbostock/3074470">'
@@ -1605,7 +1604,7 @@ class HeatmapViz(BaseViz):
         if overall:
             df['perc'] = (df.v - min_) / (max_ - min_)
         return {
-            'records': df.to_dict(orient="records"),
+            'records': df.to_dict(orient='records'),
             'extents': [min_, max_],
         }
 
@@ -1617,8 +1616,8 @@ class HorizonViz(NVD3TimeSeriesViz):
     https://www.npmjs.com/package/d3-horizon-chart
     """
 
-    viz_type = "horizon"
-    verbose_name = _("Horizon Charts")
+    viz_type = 'horizon'
+    verbose_name = _('Horizon Charts')
     credits = (
         '<a href="https://www.npmjs.com/package/d3-horizon-chart">'
         'd3-horizon-chart</a>')
@@ -1628,8 +1627,8 @@ class MapboxViz(BaseViz):
 
     """Rich maps made with Mapbox"""
 
-    viz_type = "mapbox"
-    verbose_name = _("Mapbox")
+    viz_type = 'mapbox'
+    verbose_name = _('Mapbox')
     is_timeseries = False
     credits = (
         '<a href=https://www.mapbox.com/mapbox-gl-js/api/>Mapbox GL JS</a>')
@@ -1643,7 +1642,7 @@ class MapboxViz(BaseViz):
             d['columns'] = [fd.get('all_columns_x'), fd.get('all_columns_y')]
 
             if label_col and len(label_col) >= 1:
-                if label_col[0] == "count":
+                if label_col[0] == 'count':
                     raise Exception(_(
                         "Must have a [Group By] column to have 'count' as the [Label]"))
                 d['columns'].append(label_col[0])
@@ -1655,20 +1654,20 @@ class MapboxViz(BaseViz):
         else:
             # Ensuring columns chosen are all in group by
             if (label_col and len(label_col) >= 1 and
-                    label_col[0] != "count" and
+                    label_col[0] != 'count' and
                     label_col[0] not in fd.get('groupby')):
                 raise Exception(_(
-                    "Choice of [Label] must be present in [Group By]"))
+                    'Choice of [Label] must be present in [Group By]'))
 
-            if (fd.get("point_radius") != "Auto" and
-                    fd.get("point_radius") not in fd.get('groupby')):
+            if (fd.get('point_radius') != 'Auto' and
+                    fd.get('point_radius') not in fd.get('groupby')):
                 raise Exception(_(
-                    "Choice of [Point Radius] must be present in [Group By]"))
+                    'Choice of [Point Radius] must be present in [Group By]'))
 
             if (fd.get('all_columns_x') not in fd.get('groupby') or
                     fd.get('all_columns_y') not in fd.get('groupby')):
                 raise Exception(_(
-                    "[Longitude] and [Latitude] columns must be present in [Group By]"))
+                    '[Longitude] and [Latitude] columns must be present in [Group By]'))
         return d
 
     def get_data(self, df):
@@ -1685,22 +1684,22 @@ class MapboxViz(BaseViz):
                 metric_col = df[label_col[0]]
         point_radius_col = (
             [None] * len(df.index)
-            if fd.get("point_radius") == "Auto"
-            else df[fd.get("point_radius")])
+            if fd.get('point_radius') == 'Auto'
+            else df[fd.get('point_radius')])
 
         # using geoJSON formatting
         geo_json = {
-            "type": "FeatureCollection",
-            "features": [
+            'type': 'FeatureCollection',
+            'features': [
                 {
-                    "type": "Feature",
-                    "properties": {
-                        "metric": metric,
-                        "radius": point_radius,
+                    'type': 'Feature',
+                    'properties': {
+                        'metric': metric,
+                        'radius': point_radius,
                     },
-                    "geometry": {
-                        "type": "Point",
-                        "coordinates": [lon, lat],
+                    'geometry': {
+                        'type': 'Point',
+                        'coordinates': [lon, lat],
                     },
                 }
                 for lon, lat, metric, point_radius
@@ -1712,28 +1711,28 @@ class MapboxViz(BaseViz):
         }
 
         return {
-            "geoJSON": geo_json,
-            "customMetric": custom_metric,
-            "mapboxApiKey": config.get('MAPBOX_API_KEY'),
-            "mapStyle": fd.get("mapbox_style"),
-            "aggregatorName": fd.get("pandas_aggfunc"),
-            "clusteringRadius": fd.get("clustering_radius"),
-            "pointRadiusUnit": fd.get("point_radius_unit"),
-            "globalOpacity": fd.get("global_opacity"),
-            "viewportLongitude": fd.get("viewport_longitude"),
-            "viewportLatitude": fd.get("viewport_latitude"),
-            "viewportZoom": fd.get("viewport_zoom"),
-            "renderWhileDragging": fd.get("render_while_dragging"),
-            "tooltip": fd.get("rich_tooltip"),
-            "color": fd.get("mapbox_color"),
+            'geoJSON': geo_json,
+            'customMetric': custom_metric,
+            'mapboxApiKey': config.get('MAPBOX_API_KEY'),
+            'mapStyle': fd.get('mapbox_style'),
+            'aggregatorName': fd.get('pandas_aggfunc'),
+            'clusteringRadius': fd.get('clustering_radius'),
+            'pointRadiusUnit': fd.get('point_radius_unit'),
+            'globalOpacity': fd.get('global_opacity'),
+            'viewportLongitude': fd.get('viewport_longitude'),
+            'viewportLatitude': fd.get('viewport_latitude'),
+            'viewportZoom': fd.get('viewport_zoom'),
+            'renderWhileDragging': fd.get('render_while_dragging'),
+            'tooltip': fd.get('rich_tooltip'),
+            'color': fd.get('mapbox_color'),
         }
 
 
 class EventFlowViz(BaseViz):
     """A visualization to explore patterns in event sequences"""
 
-    viz_type = "event_flow"
-    verbose_name = _("Event flow")
+    viz_type = 'event_flow'
+    verbose_name = _('Event flow')
     credits = 'from <a href="https://github.com/williaster/data-ui">@data-ui</a>'
     is_timeseries = True
 
@@ -1756,7 +1755,7 @@ class EventFlowViz(BaseViz):
         return query
 
     def get_data(self, df):
-        return df.to_dict(orient="records")
+        return df.to_dict(orient='records')
 
 
 class PairedTTestViz(BaseViz):
@@ -1764,7 +1763,7 @@ class PairedTTestViz(BaseViz):
     """A table displaying paired t-test values"""
 
     viz_type = 'paired_ttest'
-    verbose_name = _("Time Series - Paired t-test")
+    verbose_name = _('Time Series - Paired t-test')
     sort_series = False
     is_timeseries = True
 
@@ -1772,7 +1771,7 @@ class PairedTTestViz(BaseViz):
         """
         Transform received data frame into an object of the form:
         {
-            "metric1": [
+            'metric1': [
                 {
                     groups: ('groupA', ... ),
                     values: [ {x, y}, ... ],
@@ -1826,7 +1825,7 @@ class PartitionViz(NVD3TimeSeriesViz):
     """
 
     viz_type = 'partition'
-    verbose_name = _("Partition Diagram")
+    verbose_name = _('Partition Diagram')
 
     def query_obj(self):
         query_obj = super(PartitionViz, self).query_obj()
diff --git a/tests/access_tests.py b/tests/access_tests.py
index 437a75e..2f8140f 100644
--- a/tests/access_tests.py
+++ b/tests/access_tests.py
@@ -446,7 +446,7 @@ class RequestAccessTests(SupersetTestCase):
         # request access to the table
         resp = self.get_resp(
             ACCESS_REQUEST.format('table', table_1_id, 'go'))
-        assert "Access was requested" in resp
+        assert 'Access was requested' in resp
         access_request1 = self.get_access_requests('gamma', 'table', table_1_id)
         assert access_request1 is not None
 
@@ -463,7 +463,7 @@ class RequestAccessTests(SupersetTestCase):
             alpha_role,
             sm.find_permission_view_menu('datasource_access', table3_perm))
         sm.add_permission_role(
-            sm.find_role("energy_usage_role"),
+            sm.find_role('energy_usage_role'),
             sm.find_permission_view_menu('datasource_access', table3_perm))
         session.commit()
 
diff --git a/tests/base_tests.py b/tests/base_tests.py
index f18dfe2..1b213fa 100644
--- a/tests/base_tests.py
+++ b/tests/base_tests.py
@@ -19,7 +19,7 @@ from superset.security import sync_role_definitions
 
 os.environ['SUPERSET_CONFIG'] = 'tests.superset_test_config'
 
-BASE_DIR = app.config.get("BASE_DIR")
+BASE_DIR = app.config.get('BASE_DIR')
 
 
 class SupersetTestCase(unittest.TestCase):
@@ -32,9 +32,9 @@ class SupersetTestCase(unittest.TestCase):
             not os.environ.get('SOLO_TEST') and
             not os.environ.get('examples_loaded')
         ):
-            logging.info("Loading examples")
+            logging.info('Loading examples')
             cli.load_examples(load_test_data=True)
-            logging.info("Done loading examples")
+            logging.info('Done loading examples')
             sync_role_definitions()
             os.environ['examples_loaded'] = '1'
         else:
@@ -43,7 +43,7 @@ class SupersetTestCase(unittest.TestCase):
         self.client = app.test_client()
         self.maxDiff = None
 
-        gamma_sqllab_role = sm.add_role("gamma_sqllab")
+        gamma_sqllab_role = sm.add_role('gamma_sqllab')
         for perm in sm.find_role('Gamma').permissions:
             sm.add_permission_role(gamma_sqllab_role, perm)
         db_perm = self.get_main_database(sm.get_session).perm
@@ -92,11 +92,11 @@ class SupersetTestCase(unittest.TestCase):
         session = db.session
         cluster = (
             session.query(DruidCluster)
-            .filter_by(cluster_name="druid_test")
+            .filter_by(cluster_name='druid_test')
             .first()
         )
         if not cluster:
-            cluster = DruidCluster(cluster_name="druid_test")
+            cluster = DruidCluster(cluster_name='druid_test')
             session.add(cluster)
             session.commit()
 
@@ -155,7 +155,7 @@ class SupersetTestCase(unittest.TestCase):
             resp = self.client.get(url, follow_redirects=follow_redirects)
         if raise_on_error and resp.status_code > 400:
             raise Exception(
-                "http request failed with code {}".format(resp.status_code))
+                'http request failed with code {}'.format(resp.status_code))
         return resp.data.decode('utf-8')
 
     def get_json_resp(
@@ -214,7 +214,7 @@ class SupersetTestCase(unittest.TestCase):
                       client_id=client_id),
         )
         if raise_on_error and 'error' in resp:
-            raise Exception("run_sql failed")
+            raise Exception('run_sql failed')
         return resp
 
     def test_gamma_permissions(self):
diff --git a/tests/celery_tests.py b/tests/celery_tests.py
index b171b52..591e793 100644
--- a/tests/celery_tests.py
+++ b/tests/celery_tests.py
@@ -40,32 +40,32 @@ class UtilityFunctionTests(SupersetTestCase):
 
     # TODO(bkyryliuk): support more cases in CTA function.
     def test_create_table_as(self):
-        q = SupersetQuery("SELECT * FROM outer_space;")
+        q = SupersetQuery('SELECT * FROM outer_space;')
 
         self.assertEqual(
-            "CREATE TABLE tmp AS \nSELECT * FROM outer_space",
-            q.as_create_table("tmp"))
+            'CREATE TABLE tmp AS \nSELECT * FROM outer_space',
+            q.as_create_table('tmp'))
 
         self.assertEqual(
-            "DROP TABLE IF EXISTS tmp;\n"
-            "CREATE TABLE tmp AS \nSELECT * FROM outer_space",
-            q.as_create_table("tmp", overwrite=True))
+            'DROP TABLE IF EXISTS tmp;\n'
+            'CREATE TABLE tmp AS \nSELECT * FROM outer_space',
+            q.as_create_table('tmp', overwrite=True))
 
         # now without a semicolon
-        q = SupersetQuery("SELECT * FROM outer_space")
+        q = SupersetQuery('SELECT * FROM outer_space')
         self.assertEqual(
-            "CREATE TABLE tmp AS \nSELECT * FROM outer_space",
-            q.as_create_table("tmp"))
+            'CREATE TABLE tmp AS \nSELECT * FROM outer_space',
+            q.as_create_table('tmp'))
 
         # now a multi-line query
         multi_line_query = (
-            "SELECT * FROM planets WHERE\n"
+            'SELECT * FROM planets WHERE\n'
             "Luke_Father = 'Darth Vader'")
         q = SupersetQuery(multi_line_query)
         self.assertEqual(
-            "CREATE TABLE tmp AS \nSELECT * FROM planets WHERE\n"
+            'CREATE TABLE tmp AS \nSELECT * FROM planets WHERE\n'
             "Luke_Father = 'Darth Vader'",
-            q.as_create_table("tmp"),
+            q.as_create_table('tmp'),
         )
 
 
@@ -118,8 +118,7 @@ class CeleryTestCase(SupersetTestCase):
             shell=True,
         )
         subprocess.call(
-            "ps auxww | grep 'superset worker' | awk '{print $2}' | "
-            "xargs kill -9",
+            "ps auxww | grep 'superset worker' | awk '{print $2}' | xargs kill -9",
             shell=True,
         )
 
@@ -143,22 +142,22 @@ class CeleryTestCase(SupersetTestCase):
     def test_add_limit_to_the_query(self):
         main_db = self.get_main_database(db.session)
 
-        select_query = "SELECT * FROM outer_space;"
+        select_query = 'SELECT * FROM outer_space;'
         updated_select_query = main_db.wrap_sql_limit(select_query, 100)
         # Different DB engines have their own spacing while compiling
         # the queries, that's why ' '.join(query.split()) is used.
         # In addition some of the engines do not include OFFSET 0.
         self.assertTrue(
-            "SELECT * FROM (SELECT * FROM outer_space;) AS inner_qry "
-            "LIMIT 100" in ' '.join(updated_select_query.split()),
+            'SELECT * FROM (SELECT * FROM outer_space;) AS inner_qry '
+            'LIMIT 100' in ' '.join(updated_select_query.split()),
         )
 
-        select_query_no_semicolon = "SELECT * FROM outer_space"
+        select_query_no_semicolon = 'SELECT * FROM outer_space'
         updated_select_query_no_semicolon = main_db.wrap_sql_limit(
             select_query_no_semicolon, 100)
         self.assertTrue(
-            "SELECT * FROM (SELECT * FROM outer_space) AS inner_qry "
-            "LIMIT 100" in
+            'SELECT * FROM (SELECT * FROM outer_space) AS inner_qry '
+            'LIMIT 100' in
             ' '.join(updated_select_query_no_semicolon.split()),
         )
 
@@ -167,7 +166,7 @@ class CeleryTestCase(SupersetTestCase):
         )
         updated_multi_line_query = main_db.wrap_sql_limit(multi_line_query, 100)
         self.assertTrue(
-            "SELECT * FROM (SELECT * FROM planets WHERE "
+            'SELECT * FROM (SELECT * FROM planets WHERE '
             "Luke_Father = 'Darth Vader';) AS inner_qry LIMIT 100" in
             ' '.join(updated_multi_line_query.split()),
         )
@@ -176,7 +175,7 @@ class CeleryTestCase(SupersetTestCase):
         main_db = self.get_main_database(db.session)
         db_id = main_db.id
         sql_dont_exist = 'SELECT name FROM table_dont_exist'
-        result1 = self.run_sql(db_id, sql_dont_exist, "1", cta='true')
+        result1 = self.run_sql(db_id, sql_dont_exist, '1', cta='true')
         self.assertTrue('error' in result1)
 
     def test_run_sync_query_cta(self):
@@ -187,7 +186,7 @@ class CeleryTestCase(SupersetTestCase):
         sql_where = (
             "SELECT name FROM ab_permission WHERE name='{}'".format(perm_name))
         result2 = self.run_sql(
-            db_id, sql_where, "2", tmp_table='tmp_table_2', cta='true')
+            db_id, sql_where, '2', tmp_table='tmp_table_2', cta='true')
         self.assertEqual(QueryStatus.SUCCESS, result2['query']['state'])
         self.assertEqual([], result2['data'])
         self.assertEqual([], result2['columns'])
@@ -203,7 +202,7 @@ class CeleryTestCase(SupersetTestCase):
         db_id = main_db.id
         sql_empty_result = 'SELECT * FROM ab_user WHERE id=666'
         result3 = self.run_sql(
-            db_id, sql_empty_result, "3", tmp_table='tmp_table_3', cta='true')
+            db_id, sql_empty_result, '3', tmp_table='tmp_table_3', cta='true')
         self.assertEqual(QueryStatus.SUCCESS, result3['query']['state'])
         self.assertEqual([], result3['data'])
         self.assertEqual([], result3['columns'])
@@ -216,7 +215,7 @@ class CeleryTestCase(SupersetTestCase):
         eng = main_db.get_sqla_engine()
         sql_where = "SELECT name FROM ab_role WHERE name='Admin'"
         result = self.run_sql(
-            main_db.id, sql_where, "4", async='true', tmp_table='tmp_async_1',
+            main_db.id, sql_where, '4', async='true', tmp_table='tmp_async_1',
             cta='true')
         assert result['query']['state'] in (
             QueryStatus.PENDING, QueryStatus.RUNNING, QueryStatus.SUCCESS)
@@ -228,10 +227,10 @@ class CeleryTestCase(SupersetTestCase):
         self.assertEqual(QueryStatus.SUCCESS, query.status)
         self.assertEqual([{'name': 'Admin'}], df.to_dict(orient='records'))
         self.assertEqual(QueryStatus.SUCCESS, query.status)
-        self.assertTrue("FROM tmp_async_1" in query.select_sql)
-        self.assertTrue("LIMIT 666" in query.select_sql)
+        self.assertTrue('FROM tmp_async_1' in query.select_sql)
+        self.assertTrue('LIMIT 666' in query.select_sql)
         self.assertEqual(
-            "CREATE TABLE tmp_async_1 AS \nSELECT name FROM ab_role "
+            'CREATE TABLE tmp_async_1 AS \nSELECT name FROM ab_role '
             "WHERE name='Admin'", query.executed_sql)
         self.assertEqual(sql_where, query.sql)
         self.assertEqual(0, query.rows)
@@ -254,7 +253,7 @@ class CeleryTestCase(SupersetTestCase):
 
     def test_get_columns(self):
         main_db = self.get_main_database(db.session)
-        df = main_db.get_df("SELECT * FROM multiformat_time_series", None)
+        df = main_db.get_df('SELECT * FROM multiformat_time_series', None)
         cdf = dataframe.SupersetDataFrame(df)
 
         # Making ordering non-deterministic
diff --git a/tests/core_tests.py b/tests/core_tests.py
index 44da324..a821064 100644
--- a/tests/core_tests.py
+++ b/tests/core_tests.py
@@ -68,7 +68,7 @@ class CoreTests(SupersetTestCase):
 
     def test_slice_endpoint(self):
         self.login(username='admin')
-        slc = self.get_slice("Girls", db.session)
+        slc = self.get_slice('Girls', db.session)
         resp = self.get_resp('/superset/slice/{}/'.format(slc.id))
         assert 'Time Column' in resp
         assert 'List Roles' in resp
@@ -80,7 +80,7 @@ class CoreTests(SupersetTestCase):
 
     def test_slice_json_endpoint(self):
         self.login(username='admin')
-        slc = self.get_slice("Girls", db.session)
+        slc = self.get_slice('Girls', db.session)
 
         json_endpoint = (
             '/superset/explore_json/{}/{}?form_data={}'
@@ -91,7 +91,7 @@ class CoreTests(SupersetTestCase):
 
     def test_slice_csv_endpoint(self):
         self.login(username='admin')
-        slc = self.get_slice("Girls", db.session)
+        slc = self.get_slice('Girls', db.session)
 
         csv_endpoint = (
             '/superset/explore_json/{}/{}?csv=true&form_data={}'
@@ -129,16 +129,16 @@ class CoreTests(SupersetTestCase):
 
     def test_save_slice(self):
         self.login(username='admin')
-        slice_name = "Energy Sankey"
+        slice_name = 'Energy Sankey'
         slice_id = self.get_slice(slice_name, db.session).id
         db.session.commit()
-        copy_name = "Test Sankey Save"
+        copy_name = 'Test Sankey Save'
         tbl_id = self.table_ids.get('energy_usage')
-        new_slice_name = "Test Sankey Overwirte"
+        new_slice_name = 'Test Sankey Overwirte'
 
         url = (
-            "/superset/explore/table/{}/?slice_name={}&"
-            "action={}&datasource_name=energy_usage&form_data={}")
+            '/superset/explore/table/{}/?slice_name={}&'
+            'action={}&datasource_name=energy_usage&form_data={}')
 
         form_data = {
             'viz_type': 'sankey',
@@ -183,17 +183,17 @@ class CoreTests(SupersetTestCase):
 
     def test_filter_endpoint(self):
         self.login(username='admin')
-        slice_name = "Energy Sankey"
+        slice_name = 'Energy Sankey'
         slice_id = self.get_slice(slice_name, db.session).id
         db.session.commit()
         tbl_id = self.table_ids.get('energy_usage')
         table = db.session.query(SqlaTable).filter(SqlaTable.id == tbl_id)
         table.filter_select_enabled = True
         url = (
-            "/superset/filter/table/{}/target/?viz_type=sankey&groupby=source"
-            "&metric=sum__value&flt_col_0=source&flt_op_0=in&flt_eq_0=&"
-            "slice_id={}&datasource_name=energy_usage&"
-            "datasource_id=1&datasource_type=table")
+            '/superset/filter/table/{}/target/?viz_type=sankey&groupby=source'
+            '&metric=sum__value&flt_col_0=source&flt_op_0=in&flt_eq_0=&'
+            'slice_id={}&datasource_name=energy_usage&'
+            'datasource_id=1&datasource_type=table')
 
         # Changing name
         resp = self.get_resp(url.format(tbl_id, slice_id))
@@ -211,7 +211,7 @@ class CoreTests(SupersetTestCase):
                 (slc.slice_name, 'slice_id_url', slc.slice_id_url),
             ]
         for name, method, url in urls:
-            logging.info("[{name}]/[{method}]: {url}".format(**locals()))
+            logging.info('[{name}]/[{method}]: {url}'.format(**locals()))
             self.client.get(url)
 
     def test_tablemodelview_list(self):
@@ -250,7 +250,7 @@ class CoreTests(SupersetTestCase):
                 (slc.slice_name, 'slice_url', slc.slice_url),
             ]
         for name, method, url in urls:
-            print("[{name}]/[{method}]: {url}".format(**locals()))
+            print('[{name}]/[{method}]: {url}'.format(**locals()))
             response = self.client.get(url)
 
     def test_dashboard(self):
@@ -266,12 +266,12 @@ class CoreTests(SupersetTestCase):
         for mod in modules:
             failed, tests = doctest.testmod(mod)
             if failed:
-                raise Exception("Failed a doctest")
+                raise Exception('Failed a doctest')
 
     def test_misc(self):
-        assert self.get_resp('/health') == "OK"
-        assert self.get_resp('/healthcheck') == "OK"
-        assert self.get_resp('/ping') == "OK"
+        assert self.get_resp('/health') == 'OK'
+        assert self.get_resp('/healthcheck') == 'OK'
+        assert self.get_resp('/ping') == 'OK'
 
     def test_testconn(self, username='admin'):
         self.login(username=username)
@@ -308,12 +308,12 @@ class CoreTests(SupersetTestCase):
         conn_pre = sqla.engine.url.make_url(database.sqlalchemy_uri_decrypted)
 
         def custom_password_store(uri):
-            return "password_store_test"
+            return 'password_store_test'
 
         database.custom_password_store = custom_password_store
         conn = sqla.engine.url.make_url(database.sqlalchemy_uri_decrypted)
         if conn_pre.password:
-            assert conn.password == "password_store_test"
+            assert conn.password == 'password_store_test'
             assert conn.password != conn_pre.password
 
     def test_databaseview_edit(self, username='admin'):
@@ -330,7 +330,7 @@ class CoreTests(SupersetTestCase):
         self.assertEqual(sqlalchemy_uri_decrypted, database.sqlalchemy_uri_decrypted)
 
     def test_warm_up_cache(self):
-        slc = self.get_slice("Girls", db.session)
+        slc = self.get_slice('Girls', db.session)
         data = self.get_json_resp(
             '/superset/warm_up_cache?slice_id={}'.format(slc.id))
 
@@ -343,12 +343,12 @@ class CoreTests(SupersetTestCase):
     def test_shortner(self):
         self.login(username='admin')
         data = (
-            "//superset/explore/table/1/?viz_type=sankey&groupby=source&"
-            "groupby=target&metric=sum__value&row_limit=5000&where=&having=&"
-            "flt_col_0=source&flt_op_0=in&flt_eq_0=&slice_id=78&slice_name="
-            "Energy+Sankey&collapsed_fieldsets=&action=&datasource_name="
-            "energy_usage&datasource_id=1&datasource_type=table&"
-            "previous_viz_type=sankey"
+            '//superset/explore/table/1/?viz_type=sankey&groupby=source&'
+            'groupby=target&metric=sum__value&row_limit=5000&where=&having=&'
+            'flt_col_0=source&flt_op_0=in&flt_eq_0=&slice_id=78&slice_name='
+            'Energy+Sankey&collapsed_fieldsets=&action=&datasource_name='
+            'energy_usage&datasource_id=1&datasource_type=table&'
+            'previous_viz_type=sankey'
         )
         resp = self.client.post('/r/shortner/', data=data)
         assert '/r/' in resp.data.decode('utf-8')
@@ -383,7 +383,7 @@ class CoreTests(SupersetTestCase):
     def test_save_dash(self, username='admin'):
         self.login(username=username)
         dash = db.session.query(models.Dashboard).filter_by(
-            slug="births").first()
+            slug='births').first()
         positions = []
         for i, slc in enumerate(dash.slices):
             d = {
@@ -401,12 +401,12 @@ class CoreTests(SupersetTestCase):
         }
         url = '/superset/save_dash/{}/'.format(dash.id)
         resp = self.get_resp(url, data=dict(data=json.dumps(data)))
-        self.assertIn("SUCCESS", resp)
+        self.assertIn('SUCCESS', resp)
 
     def test_save_dash_with_filter(self, username='admin'):
         self.login(username=username)
         dash = db.session.query(models.Dashboard).filter_by(
-            slug="world_health").first()
+            slug='world_health').first()
         positions = []
         for i, slc in enumerate(dash.slices):
             d = {
@@ -429,21 +429,21 @@ class CoreTests(SupersetTestCase):
 
         url = '/superset/save_dash/{}/'.format(dash.id)
         resp = self.get_resp(url, data=dict(data=json.dumps(data)))
-        self.assertIn("SUCCESS", resp)
+        self.assertIn('SUCCESS', resp)
 
         updatedDash = db.session.query(models.Dashboard).filter_by(
-            slug="world_health").first()
+            slug='world_health').first()
         new_url = updatedDash.url
-        self.assertIn("region", new_url)
+        self.assertIn('region', new_url)
 
         resp = self.get_resp(new_url)
-        self.assertIn("North America", resp)
+        self.assertIn('North America', resp)
 
     def test_save_dash_with_dashboard_title(self, username='admin'):
         self.login(username=username)
         dash = (
             db.session.query(models.Dashboard)
-            .filter_by(slug="births")
+            .filter_by(slug='births')
             .first()
         )
         origin_title = dash.dashboard_title
@@ -466,7 +466,7 @@ class CoreTests(SupersetTestCase):
         self.get_resp(url, data=dict(data=json.dumps(data)))
         updatedDash = (
             db.session.query(models.Dashboard)
-            .filter_by(slug="births")
+            .filter_by(slug='births')
             .first()
         )
         self.assertEqual(updatedDash.dashboard_title, 'new title')
@@ -477,7 +477,7 @@ class CoreTests(SupersetTestCase):
     def test_copy_dash(self, username='admin'):
         self.login(username=username)
         dash = db.session.query(models.Dashboard).filter_by(
-            slug="births").first()
+            slug='births').first()
         positions = []
         for i, slc in enumerate(dash.slices):
             d = {
@@ -514,37 +514,37 @@ class CoreTests(SupersetTestCase):
     def test_add_slices(self, username='admin'):
         self.login(username=username)
         dash = db.session.query(models.Dashboard).filter_by(
-            slug="births").first()
+            slug='births').first()
         new_slice = db.session.query(models.Slice).filter_by(
-            slice_name="Mapbox Long/Lat").first()
+            slice_name='Mapbox Long/Lat').first()
         existing_slice = db.session.query(models.Slice).filter_by(
-            slice_name="Name Cloud").first()
+            slice_name='Name Cloud').first()
         data = {
-            "slice_ids": [new_slice.data["slice_id"],
-                          existing_slice.data["slice_id"]],
+            'slice_ids': [new_slice.data['slice_id'],
+                          existing_slice.data['slice_id']],
         }
         url = '/superset/add_slices/{}/'.format(dash.id)
         resp = self.client.post(url, data=dict(data=json.dumps(data)))
-        assert "SLICES ADDED" in resp.data.decode('utf-8')
+        assert 'SLICES ADDED' in resp.data.decode('utf-8')
 
         dash = db.session.query(models.Dashboard).filter_by(
-            slug="births").first()
+            slug='births').first()
         new_slice = db.session.query(models.Slice).filter_by(
-            slice_name="Mapbox Long/Lat").first()
+            slice_name='Mapbox Long/Lat').first()
         assert new_slice in dash.slices
         assert len(set(dash.slices)) == len(dash.slices)
 
         # cleaning up
         dash = db.session.query(models.Dashboard).filter_by(
-            slug="births").first()
+            slug='births').first()
         dash.slices = [
-            o for o in dash.slices if o.slice_name != "Mapbox Long/Lat"]
+            o for o in dash.slices if o.slice_name != 'Mapbox Long/Lat']
         db.session.commit()
 
     def test_gamma(self):
         self.login(username='gamma')
-        assert "List Slice" in self.get_resp('/slicemodelview/list/')
-        assert "List Dashboard" in self.get_resp('/dashboardmodelview/list/')
+        assert 'List Slice' in self.get_resp('/slicemodelview/list/')
+        assert 'List Dashboard' in self.get_resp('/dashboardmodelview/list/')
 
     def test_csv_endpoint(self):
         self.login('admin')
@@ -553,13 +553,13 @@ class CoreTests(SupersetTestCase):
             FROM ab_user
             WHERE first_name='admin'
         """
-        client_id = "{}".format(random.getrandbits(64))[:10]
+        client_id = '{}'.format(random.getrandbits(64))[:10]
         self.run_sql(sql, client_id, raise_on_error=True)
 
         resp = self.get_resp('/superset/csv/{}'.format(client_id))
         data = csv.reader(io.StringIO(resp))
         expected_data = csv.reader(
-            io.StringIO("first_name,last_name\nadmin, user\n"))
+            io.StringIO('first_name,last_name\nadmin, user\n'))
 
         self.assertEqual(list(expected_data), list(data))
         self.logout()
@@ -587,7 +587,7 @@ class CoreTests(SupersetTestCase):
         self.assertIn('birth_names', self.get_resp('/slicemodelview/list/'))
 
         resp = self.get_resp('/dashboardmodelview/list/')
-        self.assertIn("/superset/dashboard/births/", resp)
+        self.assertIn('/superset/dashboard/births/', resp)
 
         self.assertIn('Births', self.get_resp('/superset/dashboard/births/'))
 
@@ -596,7 +596,7 @@ class CoreTests(SupersetTestCase):
         self.assertNotIn('wb_health_population</a>', resp)
 
         resp = self.get_resp('/dashboardmodelview/list/')
-        self.assertNotIn("/superset/dashboard/world_health/", resp)
+        self.assertNotIn('/superset/dashboard/world_health/', resp)
 
     def test_dashboard_with_created_by_can_be_accessed_by_public_users(self):
         self.logout()
@@ -609,7 +609,7 @@ class CoreTests(SupersetTestCase):
         self.grant_public_access_to_table(table)
 
         dash = db.session.query(models.Dashboard).filter_by(
-            slug="births").first()
+            slug='births').first()
         dash.owners = [appbuilder.sm.find_user('admin')]
         dash.created_by = appbuilder.sm.find_user('admin')
         db.session.merge(dash)
@@ -621,7 +621,7 @@ class CoreTests(SupersetTestCase):
         dash = (
             db.session
             .query(models.Dashboard)
-            .filter_by(slug="births")
+            .filter_by(slug='births')
             .first()
         )
         dash.owners = []
@@ -638,7 +638,7 @@ class CoreTests(SupersetTestCase):
         dash = (
             db.session
             .query(models.Dashboard)
-            .filter_by(slug="births")
+            .filter_by(slug='births')
             .first()
         )
         dash.owners = [alpha]
@@ -662,29 +662,29 @@ class CoreTests(SupersetTestCase):
 
     def test_get_template_kwarg(self):
         maindb = self.get_main_database(db.session)
-        s = "{{ foo }}"
+        s = '{{ foo }}'
         tp = jinja_context.get_template_processor(database=maindb, foo='bar')
         rendered = tp.process_template(s)
-        self.assertEqual("bar", rendered)
+        self.assertEqual('bar', rendered)
 
     def test_template_kwarg(self):
         maindb = self.get_main_database(db.session)
-        s = "{{ foo }}"
+        s = '{{ foo }}'
         tp = jinja_context.get_template_processor(database=maindb)
         rendered = tp.process_template(s, foo='bar')
-        self.assertEqual("bar", rendered)
+        self.assertEqual('bar', rendered)
 
     def test_templated_sql_json(self):
         self.login('admin')
         sql = "SELECT '{{ datetime(2017, 1, 1).isoformat() }}' as test"
-        data = self.run_sql(sql, "fdaklj3ws")
-        self.assertEqual(data['data'][0]['test'], "2017-01-01T00:00:00")
+        data = self.run_sql(sql, 'fdaklj3ws')
+        self.assertEqual(data['data'][0]['test'], '2017-01-01T00:00:00')
 
     def test_table_metadata(self):
         maindb = self.get_main_database(db.session)
         backend = maindb.backend
         data = self.get_json_resp(
-            "/superset/table/{}/ab_user/null/".format(maindb.id))
+            '/superset/table/{}/ab_user/null/'.format(maindb.id))
         self.assertEqual(data['name'], 'ab_user')
         assert len(data['columns']) > 5
         assert data.get('selectStar').startswith('SELECT')
@@ -717,7 +717,7 @@ class CoreTests(SupersetTestCase):
 
     def test_user_profile(self, username='admin'):
         self.login(username=username)
-        slc = self.get_slice("Girls", db.session)
+        slc = self.get_slice('Girls', db.session)
 
         # Setting some faves
         url = '/superset/favstar/Slice/{}/select/'.format(slc.id)
@@ -727,7 +727,7 @@ class CoreTests(SupersetTestCase):
         dash = (
             db.session
             .query(models.Dashboard)
-            .filter_by(slug="births")
+            .filter_by(slug='births')
             .first()
         )
         url = '/superset/favstar/Dashboard/{}/select/'.format(dash.id)
@@ -760,24 +760,24 @@ class CoreTests(SupersetTestCase):
 
     def test_slice_id_is_always_logged_correctly_on_ajax_request(self):
         # superset/explore_json case
-        self.login(username="admin")
+        self.login(username='admin')
         slc = db.session.query(models.Slice).filter_by(slice_name='Girls').one()
         qry = db.session.query(models.Log).filter_by(slice_id=slc.id)
-        slc_url = slc.slice_url.replace("explore", "explore_json")
+        slc_url = slc.slice_url.replace('explore', 'explore_json')
         self.get_json_resp(slc_url)
         self.assertEqual(1, qry.count())
 
     def test_slice_query_endpoint(self):
         # API endpoint for query string
-        self.login(username="admin")
-        slc = self.get_slice("Girls", db.session)
+        self.login(username='admin')
+        slc = self.get_slice('Girls', db.session)
         resp = self.get_resp('/superset/slice_query/{}/'.format(slc.id))
         assert 'query' in resp
         assert 'language' in resp
         self.logout()
 
     def test_viz_get_fillna_for_columns(self):
-        slc = self.get_slice("Girls", db.session)
+        slc = self.get_slice('Girls', db.session)
         q = slc.viz.query_obj()
         results = slc.viz.datasource.query(q)
         fillna_columns = slc.viz.get_fillna_for_columns(results.df.columns)
diff --git a/tests/druid_tests.py b/tests/druid_tests.py
index b8250f3..76320bf 100644
--- a/tests/druid_tests.py
+++ b/tests/druid_tests.py
@@ -23,47 +23,47 @@ class PickableMock(Mock):
 
 
 SEGMENT_METADATA = [{
-    "id": "some_id",
-    "intervals": ["2013-05-13T00:00:00.000Z/2013-05-14T00:00:00.000Z"],
-    "columns": {
-        "__time": {
-            "type": "LONG", "hasMultipleValues": False,
-            "size": 407240380, "cardinality": None, "errorMessage": None},
-        "dim1": {
-            "type": "STRING", "hasMultipleValues": False,
-            "size": 100000, "cardinality": 1944, "errorMessage": None},
-        "dim2": {
-            "type": "STRING", "hasMultipleValues": True,
-            "size": 100000, "cardinality": 1504, "errorMessage": None},
-        "metric1": {
-            "type": "FLOAT", "hasMultipleValues": False,
-            "size": 100000, "cardinality": None, "errorMessage": None},
+    'id': 'some_id',
+    'intervals': ['2013-05-13T00:00:00.000Z/2013-05-14T00:00:00.000Z'],
+    'columns': {
+        '__time': {
+            'type': 'LONG', 'hasMultipleValues': False,
+            'size': 407240380, 'cardinality': None, 'errorMessage': None},
+        'dim1': {
+            'type': 'STRING', 'hasMultipleValues': False,
+            'size': 100000, 'cardinality': 1944, 'errorMessage': None},
+        'dim2': {
+            'type': 'STRING', 'hasMultipleValues': True,
+            'size': 100000, 'cardinality': 1504, 'errorMessage': None},
+        'metric1': {
+            'type': 'FLOAT', 'hasMultipleValues': False,
+            'size': 100000, 'cardinality': None, 'errorMessage': None},
     },
-    "aggregators": {
-        "metric1": {
-            "type": "longSum",
-            "name": "metric1",
-            "fieldName": "metric1"},
+    'aggregators': {
+        'metric1': {
+            'type': 'longSum',
+            'name': 'metric1',
+            'fieldName': 'metric1'},
     },
-    "size": 300000,
-    "numRows": 5000000,
+    'size': 300000,
+    'numRows': 5000000,
 }]
 
 GB_RESULT_SET = [
     {
-        "version": "v1",
-        "timestamp": "2012-01-01T00:00:00.000Z",
-        "event": {
-            "dim1": 'Canada',
-            "metric1": 12345678,
+        'version': 'v1',
+        'timestamp': '2012-01-01T00:00:00.000Z',
+        'event': {
+            'dim1': 'Canada',
+            'metric1': 12345678,
         },
     },
     {
-        "version": "v1",
-        "timestamp": "2012-01-01T00:00:00.000Z",
-        "event": {
-            "dim1": 'USA',
-            "metric1": 12345678 / 2,
+        'version': 'v1',
+        'timestamp': '2012-01-01T00:00:00.000Z',
+        'event': {
+            'dim1': 'USA',
+            'metric1': 12345678 / 2,
         },
     },
 ]
@@ -122,7 +122,7 @@ class DruidTests(SupersetTestCase):
 
         resp = self.get_resp('/superset/explore/druid/{}/'.format(
             datasource_id))
-        self.assertIn("test_datasource", resp)
+        self.assertIn('test_datasource', resp)
         form_data = {
             'viz_type': 'table',
             'granularity': 'one+day',
@@ -141,7 +141,7 @@ class DruidTests(SupersetTestCase):
                 datasource_id, json.dumps(form_data))
         )
         resp = self.get_json_resp(url)
-        self.assertEqual("Canada", resp['data']['records'][0]['dim1'])
+        self.assertEqual('Canada', resp['data']['records'][0]['dim1'])
 
         form_data = {
             'viz_type': 'table',
@@ -161,7 +161,7 @@ class DruidTests(SupersetTestCase):
                 datasource_id, json.dumps(form_data))
         )
         resp = self.get_json_resp(url)
-        self.assertEqual("Canada", resp['data']['records'][0]['dim1'])
+        self.assertEqual('Canada', resp['data']['records'][0]['dim1'])
 
     def test_druid_sync_from_config(self):
         CLUSTER_NAME = 'new_druid'
@@ -184,19 +184,19 @@ class DruidTests(SupersetTestCase):
         db.session.commit()
 
         cfg = {
-            "user": "admin",
-            "cluster": CLUSTER_NAME,
-            "config": {
-                "name": "test_click",
-                "dimensions": ["affiliate_id", "campaign", "first_seen"],
-                "metrics_spec": [{"type": "count", "name": "count"},
-                                 {"type": "sum", "name": "sum"}],
-                "batch_ingestion": {
-                    "sql": "SELECT * FROM clicks WHERE d='{{ ds }}'",
-                    "ts_column": "d",
-                    "sources": [{
-                        "table": "clicks",
-                        "partition": "d='{{ ds }}'",
+            'user': 'admin',
+            'cluster': CLUSTER_NAME,
+            'config': {
+                'name': 'test_click',
+                'dimensions': ['affiliate_id', 'campaign', 'first_seen'],
+                'metrics_spec': [{'type': 'count', 'name': 'count'},
+                                 {'type': 'sum', 'name': 'sum'}],
+                'batch_ingestion': {
+                    'sql': "SELECT * FROM clicks WHERE d='{{ ds }}'",
+                    'ts_column': 'd',
+                    'sources': [{
+                        'table': 'clicks',
+                        'partition': "d='{{ ds }}'",
                     }],
                 },
             },
@@ -207,13 +207,13 @@ class DruidTests(SupersetTestCase):
             druid_ds = (
                 db.session
                 .query(DruidDatasource)
-                .filter_by(datasource_name="test_click")
+                .filter_by(datasource_name='test_click')
                 .one()
             )
             col_names = set([c.column_name for c in druid_ds.columns])
-            assert {"affiliate_id", "campaign", "first_seen"} == col_names
+            assert {'affiliate_id', 'campaign', 'first_seen'} == col_names
             metric_names = {m.metric_name for m in druid_ds.metrics}
-            assert {"count", "sum"} == metric_names
+            assert {'count', 'sum'} == metric_names
             assert resp.status_code == 201
 
         check()
@@ -222,29 +222,29 @@ class DruidTests(SupersetTestCase):
 
         # datasource exists, add new metrics and dimensions
         cfg = {
-            "user": "admin",
-            "cluster": CLUSTER_NAME,
-            "config": {
-                "name": "test_click",
-                "dimensions": ["affiliate_id", "second_seen"],
-                "metrics_spec": [
-                    {"type": "bla", "name": "sum"},
-                    {"type": "unique", "name": "unique"},
+            'user': 'admin',
+            'cluster': CLUSTER_NAME,
+            'config': {
+                'name': 'test_click',
+                'dimensions': ['affiliate_id', 'second_seen'],
+                'metrics_spec': [
+                    {'type': 'bla', 'name': 'sum'},
+                    {'type': 'unique', 'name': 'unique'},
                 ],
             },
         }
         resp = self.client.post('/superset/sync_druid/', data=json.dumps(cfg))
         druid_ds = db.session.query(DruidDatasource).filter_by(
-            datasource_name="test_click").one()
+            datasource_name='test_click').one()
         # columns and metrics are not deleted if config is changed as
         # user could define his own dimensions / metrics and want to keep them
         assert set([c.column_name for c in druid_ds.columns]) == set(
-            ["affiliate_id", "campaign", "first_seen", "second_seen"])
+            ['affiliate_id', 'campaign', 'first_seen', 'second_seen'])
         assert set([m.metric_name for m in druid_ds.metrics]) == set(
-            ["count", "sum", "unique"])
+            ['count', 'sum', 'unique'])
         # metric type will not be overridden, sum stays instead of bla
         assert set([m.metric_type for m in druid_ds.metrics]) == set(
-            ["longSum", "sum", "unique"])
+            ['longSum', 'sum', 'unique'])
         assert resp.status_code == 201
 
     def test_filter_druid_datasource(self):
@@ -322,7 +322,7 @@ class DruidTests(SupersetTestCase):
 
         view_menu_name = cluster.datasources[0].get_perm()
         view_menu = sm.find_view_menu(view_menu_name)
-        permission = sm.find_permission("datasource_access")
+        permission = sm.find_permission('datasource_access')
 
         pv = sm.get_session.query(sm.permissionview_model).filter_by(
             permission=permission, view_menu=view_menu).first()
@@ -511,7 +511,7 @@ class DruidTests(SupersetTestCase):
         self.assertEqual('', res.filter['filter']['value'])
 
     def test_get_filters_extracts_values_in_quotes(self):
-        filtr = {'col': 'A', 'op': 'in', 'val': ["  'a' "]}
+        filtr = {'col': 'A', 'op': 'in', 'val': ['  "a" ']}
         res = DruidDatasource.get_filters([filtr], [])
         self.assertEqual('a', res.filter['filter']['value'])
 
diff --git a/tests/import_export_tests.py b/tests/import_export_tests.py
index 8bc706a..e945630 100644
--- a/tests/import_export_tests.py
+++ b/tests/import_export_tests.py
@@ -60,9 +60,9 @@ class ImportExportTests(SupersetTestCase):
             'database_name': db_name,
             'schema': '',
             # Test for trailing commas
-            "metrics": [
-                "sum__signup_attempt_email",
-                "sum__signup_attempt_facebook",
+            'metrics': [
+                'sum__signup_attempt_email',
+                'sum__signup_attempt_facebook',
             ],
         }
 
@@ -319,7 +319,7 @@ class ImportExportTests(SupersetTestCase):
         make_transient(expected_dash)
         self.assert_dash_equals(
             expected_dash, imported_dash, check_position=False)
-        self.assertEquals({"remote_id": 10002, "import_time": 1990},
+        self.assertEquals({'remote_id': 10002, 'import_time': 1990},
                           json.loads(imported_dash.json_metadata))
 
         expected_position = dash_with_1_slice.position_array
@@ -333,11 +333,11 @@ class ImportExportTests(SupersetTestCase):
         dash_with_2_slices = self.create_dashboard(
             'dash_with_2_slices', slcs=[e_slc, b_slc], id=10003)
         dash_with_2_slices.json_metadata = json.dumps({
-            "remote_id": 10003,
-            "filter_immune_slices": ["{}".format(e_slc.id)],
-            "expanded_slices": {
-                "{}".format(e_slc.id): True,
-                "{}".format(b_slc.id): False,
+            'remote_id': 10003,
+            'filter_immune_slices': ['{}'.format(e_slc.id)],
+            'expanded_slices': {
+                '{}'.format(e_slc.id): True,
+                '{}'.format(b_slc.id): False,
             },
         })
 
@@ -353,10 +353,10 @@ class ImportExportTests(SupersetTestCase):
         i_e_slc = self.get_slice_by_name('e_slc')
         i_b_slc = self.get_slice_by_name('b_slc')
         expected_json_metadata = {
-            "remote_id": 10003,
-            "import_time": 1991,
-            "filter_immune_slices": ["{}".format(i_e_slc.id)],
-            "expanded_slices": {
+            'remote_id': 10003,
+            'import_time': 1991,
+            'filter_immune_slices': ['{}'.format(i_e_slc.id)],
+            'expanded_slices': {
                 '{}'.format(i_e_slc.id): True,
                 '{}'.format(i_b_slc.id): False,
             },
@@ -391,7 +391,7 @@ class ImportExportTests(SupersetTestCase):
         imported_dash = self.get_dash(imported_dash_id_2)
         self.assert_dash_equals(
             expected_dash, imported_dash, check_position=False)
-        self.assertEquals({"remote_id": 10004, "import_time": 1992},
+        self.assertEquals({'remote_id': 10004, 'import_time': 1992},
                           json.loads(imported_dash.json_metadata))
 
     def test_import_table_no_metadata(self):
@@ -403,7 +403,7 @@ class ImportExportTests(SupersetTestCase):
     def test_import_table_1_col_1_met(self):
         table = self.create_table(
             'table_1_col_1_met', id=10002,
-            cols_names=["col1"], metric_names=["metric1"])
+            cols_names=['col1'], metric_names=['metric1'])
         imported_id = SqlaTable.import_obj(table, import_time=1990)
         imported = self.get_table(imported_id)
         self.assert_table_equals(table, imported)
@@ -464,7 +464,7 @@ class ImportExportTests(SupersetTestCase):
     def test_import_druid_1_col_1_met(self):
         datasource = self.create_druid_datasource(
             'druid_1_col_1_met', id=10002,
-            cols_names=["col1"], metric_names=["metric1"])
+            cols_names=['col1'], metric_names=['metric1'])
         imported_id = DruidDatasource.import_obj(
             datasource, import_time=1990)
         imported = self.get_datasource(imported_id)
diff --git a/tests/sql_parse_tests.py b/tests/sql_parse_tests.py
index c9cc389..c9368bb 100644
--- a/tests/sql_parse_tests.py
+++ b/tests/sql_parse_tests.py
@@ -16,42 +16,42 @@ class SupersetTestCase(unittest.TestCase):
         return sq.tables
 
     def test_simple_select(self):
-        query = "SELECT * FROM tbname"
-        self.assertEquals({"tbname"}, self.extract_tables(query))
+        query = 'SELECT * FROM tbname'
+        self.assertEquals({'tbname'}, self.extract_tables(query))
 
         # underscores
-        query = "SELECT * FROM tb_name"
-        self.assertEquals({"tb_name"},
+        query = 'SELECT * FROM tb_name'
+        self.assertEquals({'tb_name'},
                           self.extract_tables(query))
 
         # quotes
         query = 'SELECT * FROM "tbname"'
-        self.assertEquals({"tbname"}, self.extract_tables(query))
+        self.assertEquals({'tbname'}, self.extract_tables(query))
 
         # unicode encoding
         query = 'SELECT * FROM "tb_name" WHERE city = "L├╝beck"'
-        self.assertEquals({"tb_name"}, self.extract_tables(query))
+        self.assertEquals({'tb_name'}, self.extract_tables(query))
 
         # schema
         self.assertEquals(
-            {"schemaname.tbname"},
-            self.extract_tables("SELECT * FROM schemaname.tbname"))
+            {'schemaname.tbname'},
+            self.extract_tables('SELECT * FROM schemaname.tbname'))
 
         # quotes
-        query = "SELECT field1, field2 FROM tb_name"
-        self.assertEquals({"tb_name"}, self.extract_tables(query))
+        query = 'SELECT field1, field2 FROM tb_name'
+        self.assertEquals({'tb_name'}, self.extract_tables(query))
 
-        query = "SELECT t1.f1, t2.f2 FROM t1, t2"
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        query = 'SELECT t1.f1, t2.f2 FROM t1, t2'
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
     def test_select_named_table(self):
-        query = "SELECT a.date, a.field FROM left_table a LIMIT 10"
+        query = 'SELECT a.date, a.field FROM left_table a LIMIT 10'
         self.assertEquals(
-            {"left_table"}, self.extract_tables(query))
+            {'left_table'}, self.extract_tables(query))
 
     def test_reverse_select(self):
-        query = "FROM t1 SELECT field"
-        self.assertEquals({"t1"}, self.extract_tables(query))
+        query = 'FROM t1 SELECT field'
+        self.assertEquals({'t1'}, self.extract_tables(query))
 
     def test_subselect(self):
         query = """
@@ -63,7 +63,7 @@ class SupersetTestCase(unittest.TestCase):
                    ) sub, s2.t2
           WHERE sub.resolution = 'NONE'
         """
-        self.assertEquals({"s1.t1", "s2.t2"},
+        self.assertEquals({'s1.t1', 's2.t2'},
                           self.extract_tables(query))
 
         query = """
@@ -75,7 +75,7 @@ class SupersetTestCase(unittest.TestCase):
                    ) sub
           WHERE sub.resolution = 'NONE'
         """
-        self.assertEquals({"s1.t1"}, self.extract_tables(query))
+        self.assertEquals({'s1.t1'}, self.extract_tables(query))
 
         query = """
             SELECT * FROM t1
@@ -86,25 +86,25 @@ class SupersetTestCase(unittest.TestCase):
                   WHERE ROW(5*t2.s1,77)=
                     (SELECT 50,11*s1 FROM t4)));
         """
-        self.assertEquals({"t1", "t2", "t3", "t4"},
+        self.assertEquals({'t1', 't2', 't3', 't4'},
                           self.extract_tables(query))
 
     def test_select_in_expression(self):
-        query = "SELECT f1, (SELECT count(1) FROM t2) FROM t1"
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        query = 'SELECT f1, (SELECT count(1) FROM t2) FROM t1'
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
     def test_union(self):
-        query = "SELECT * FROM t1 UNION SELECT * FROM t2"
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        query = 'SELECT * FROM t1 UNION SELECT * FROM t2'
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
-        query = "SELECT * FROM t1 UNION ALL SELECT * FROM t2"
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        query = 'SELECT * FROM t1 UNION ALL SELECT * FROM t2'
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
-        query = "SELECT * FROM t1 INTERSECT ALL SELECT * FROM t2"
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        query = 'SELECT * FROM t1 INTERSECT ALL SELECT * FROM t2'
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
     def test_select_from_values(self):
-        query = "SELECT * FROM VALUES (13, 42)"
+        query = 'SELECT * FROM VALUES (13, 42)'
         self.assertFalse(self.extract_tables(query))
 
     def test_select_array(self):
@@ -112,25 +112,25 @@ class SupersetTestCase(unittest.TestCase):
             SELECT ARRAY[1, 2, 3] AS my_array
             FROM t1 LIMIT 10
         """
-        self.assertEquals({"t1"}, self.extract_tables(query))
+        self.assertEquals({'t1'}, self.extract_tables(query))
 
     def test_select_if(self):
         query = """
             SELECT IF(CARDINALITY(my_array) >= 3, my_array[3], NULL)
             FROM t1 LIMIT 10
         """
-        self.assertEquals({"t1"}, self.extract_tables(query))
+        self.assertEquals({'t1'}, self.extract_tables(query))
 
     # SHOW TABLES ((FROM | IN) qualifiedName)? (LIKE pattern=STRING)?
     def test_show_tables(self):
-        query = 'SHOW TABLES FROM s1 like "%order%"'
+        query = "SHOW TABLES FROM s1 like '%order%'"
         # TODO: figure out what should code do here
-        self.assertEquals({"s1"}, self.extract_tables(query))
+        self.assertEquals({'s1'}, self.extract_tables(query))
 
     # SHOW COLUMNS (FROM | IN) qualifiedName
     def test_show_columns(self):
-        query = "SHOW COLUMNS FROM t1"
-        self.assertEquals({"t1"}, self.extract_tables(query))
+        query = 'SHOW COLUMNS FROM t1'
+        self.assertEquals({'t1'}, self.extract_tables(query))
 
     def test_where_subquery(self):
         query = """
@@ -138,26 +138,26 @@ class SupersetTestCase(unittest.TestCase):
             FROM t1
             WHERE regionkey = (SELECT max(regionkey) FROM t2)
         """
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
         query = """
           SELECT name
             FROM t1
             WHERE regionkey IN (SELECT regionkey FROM t2)
         """
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
         query = """
           SELECT name
             FROM t1
             WHERE regionkey EXISTS (SELECT regionkey FROM t2)
         """
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
     # DESCRIBE | DESC qualifiedName
     def test_describe(self):
-        self.assertEquals({"t1"}, self.extract_tables("DESCRIBE t1"))
-        self.assertEquals({"t1"}, self.extract_tables("DESC t1"))
+        self.assertEquals({'t1'}, self.extract_tables('DESCRIBE t1'))
+        self.assertEquals({'t1'}, self.extract_tables('DESC t1'))
 
     # SHOW PARTITIONS FROM qualifiedName (WHERE booleanExpression)?
     # (ORDER BY sortItem (',' sortItem)*)? (LIMIT limit=(INTEGER_VALUE | ALL))?
@@ -166,11 +166,11 @@ class SupersetTestCase(unittest.TestCase):
             SHOW PARTITIONS FROM orders
             WHERE ds >= '2013-01-01' ORDER BY ds DESC;
         """
-        self.assertEquals({"orders"}, self.extract_tables(query))
+        self.assertEquals({'orders'}, self.extract_tables(query))
 
     def test_join(self):
-        query = "SELECT t1.*, t2.* FROM t1 JOIN t2 ON t1.a = t2.a;"
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        query = 'SELECT t1.*, t2.* FROM t1 JOIN t2 ON t1.a = t2.a;'
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
         # subquery + join
         query = """
@@ -184,7 +184,7 @@ class SupersetTestCase(unittest.TestCase):
                 ) b
                 ON a.date = b.date
         """
-        self.assertEquals({"left_table", "right_table"},
+        self.assertEquals({'left_table', 'right_table'},
                           self.extract_tables(query))
 
         query = """
@@ -198,7 +198,7 @@ class SupersetTestCase(unittest.TestCase):
                 ) b
                 ON a.date = b.date
         """
-        self.assertEquals({"left_table", "right_table"},
+        self.assertEquals({'left_table', 'right_table'},
                           self.extract_tables(query))
 
         query = """
@@ -212,7 +212,7 @@ class SupersetTestCase(unittest.TestCase):
                 ) b
                 ON a.date = b.date
         """
-        self.assertEquals({"left_table", "right_table"},
+        self.assertEquals({'left_table', 'right_table'},
                           self.extract_tables(query))
 
         query = """
@@ -226,7 +226,7 @@ class SupersetTestCase(unittest.TestCase):
                 ) b
                 ON a.date = b.date
         """
-        self.assertEquals({"left_table", "right_table"},
+        self.assertEquals({'left_table', 'right_table'},
                           self.extract_tables(query))
 
         # TODO: add SEMI join support, SQL Parse does not handle it.
@@ -241,7 +241,7 @@ class SupersetTestCase(unittest.TestCase):
         #         ) b
         #         ON a.date = b.date
         # """
-        # self.assertEquals({"left_table", "right_table"},
+        # self.assertEquals({'left_table', 'right_table'},
         #                   sql_parse.extract_tables(query))
 
     def test_combinations(self):
@@ -255,14 +255,14 @@ class SupersetTestCase(unittest.TestCase):
                   WHERE ROW(5*t3.s1,77)=
                     (SELECT 50,11*s1 FROM t4)));
         """
-        self.assertEquals({"t1", "t3", "t4", "t6"},
+        self.assertEquals({'t1', 't3', 't4', 't6'},
                           self.extract_tables(query))
 
         query = """
         SELECT * FROM (SELECT * FROM (SELECT * FROM (SELECT * FROM EmployeeS)
             AS S1) AS S2) AS S3;
         """
-        self.assertEquals({"EmployeeS"}, self.extract_tables(query))
+        self.assertEquals({'EmployeeS'}, self.extract_tables(query))
 
     def test_with(self):
         query = """
@@ -272,7 +272,7 @@ class SupersetTestCase(unittest.TestCase):
               z AS (SELECT b AS c FROM t3)
             SELECT c FROM z;
         """
-        self.assertEquals({"t1", "t2", "t3"},
+        self.assertEquals({'t1', 't2', 't3'},
                           self.extract_tables(query))
 
         query = """
@@ -282,7 +282,7 @@ class SupersetTestCase(unittest.TestCase):
               z AS (SELECT b AS c FROM y)
             SELECT c FROM z;
         """
-        self.assertEquals({"t1"}, self.extract_tables(query))
+        self.assertEquals({'t1'}, self.extract_tables(query))
 
     def test_reusing_aliases(self):
         query = """
@@ -290,11 +290,11 @@ class SupersetTestCase(unittest.TestCase):
             q2 as ( select key from src where key = '5')
             select * from (select key from q1) a;
         """
-        self.assertEquals({"src"}, self.extract_tables(query))
+        self.assertEquals({'src'}, self.extract_tables(query))
 
     def multistatement(self):
-        query = "SELECT * FROM t1; SELECT * FROM t2"
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        query = 'SELECT * FROM t1; SELECT * FROM t2'
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
 
-        query = "SELECT * FROM t1; SELECT * FROM t2;"
-        self.assertEquals({"t1", "t2"}, self.extract_tables(query))
+        query = 'SELECT * FROM t1; SELECT * FROM t2;'
+        self.assertEquals({'t1', 't2'}, self.extract_tables(query))
diff --git a/tests/sqllab_tests.py b/tests/sqllab_tests.py
index c4332c9..2caf4c2 100644
--- a/tests/sqllab_tests.py
+++ b/tests/sqllab_tests.py
@@ -25,15 +25,15 @@ class SqlLabTests(SupersetTestCase):
         db.session.query(Query).delete()
         db.session.commit()
         self.run_sql(
-            "SELECT * FROM ab_user",
+            'SELECT * FROM ab_user',
             client_id='client_id_1',
             user_name='admin')
         self.run_sql(
-            "SELECT * FROM NO_TABLE",
+            'SELECT * FROM NO_TABLE',
             client_id='client_id_3',
             user_name='admin')
         self.run_sql(
-            "SELECT * FROM ab_permission",
+            'SELECT * FROM ab_permission',
             client_id='client_id_2',
             user_name='gamma_sqllab')
         self.logout()
@@ -46,10 +46,10 @@ class SqlLabTests(SupersetTestCase):
     def test_sql_json(self):
         self.login('admin')
 
-        data = self.run_sql('SELECT * FROM ab_user', "1")
+        data = self.run_sql('SELECT * FROM ab_user', '1')
         self.assertLess(0, len(data['data']))
 
-        data = self.run_sql('SELECT * FROM unexistant_table', "2")
+        data = self.run_sql('SELECT * FROM unexistant_table', '2')
         self.assertLess(0, len(data['error']))
 
     def test_sql_json_has_access(self):
@@ -64,7 +64,7 @@ class SqlLabTests(SupersetTestCase):
             .filter(ab_models.Permission.name == 'database_access')
             .first()
         )
-        astronaut = sm.add_role("Astronaut")
+        astronaut = sm.add_role('Astronaut')
         sm.add_permission_role(astronaut, main_db_permission_view)
         # Astronaut role is Gamma + sqllab +  main db permissions
         for perm in sm.find_role('Gamma').permissions:
@@ -78,7 +78,7 @@ class SqlLabTests(SupersetTestCase):
                 'gagarin', 'Iurii', 'Gagarin', 'gagarin@cosmos.ussr',
                 astronaut,
                 password='general')
-        data = self.run_sql('SELECT * FROM ab_user', "3", user_name='gagarin')
+        data = self.run_sql('SELECT * FROM ab_user', '3', user_name='gagarin')
         db.session.query(Query).delete()
         db.session.commit()
         self.assertLess(0, len(data['data']))
@@ -97,8 +97,8 @@ class SqlLabTests(SupersetTestCase):
         self.assertEquals(2, len(data))
 
         # Run 2 more queries
-        self.run_sql("SELECT * FROM ab_user LIMIT 1", client_id='client_id_4')
-        self.run_sql("SELECT * FROM ab_user LIMIT 2", client_id='client_id_5')
+        self.run_sql('SELECT * FROM ab_user LIMIT 1', client_id='client_id_4')
+        self.run_sql('SELECT * FROM ab_user LIMIT 2', client_id='client_id_5')
         self.login('admin')
         data = self.get_json_resp('/superset/queries/0')
         self.assertEquals(4, len(data))
@@ -195,7 +195,7 @@ class SqlLabTests(SupersetTestCase):
 
     def test_alias_duplicate(self):
         self.run_sql(
-            "SELECT username as col, id as col, username FROM ab_user",
+            'SELECT username as col, id as col, username FROM ab_user',
             client_id='2e2df3',
             user_name='admin',
             raise_on_error=True)
diff --git a/tests/utils_tests.py b/tests/utils_tests.py
index dc6b454..1d5cc65 100644
--- a/tests/utils_tests.py
+++ b/tests/utils_tests.py
@@ -24,7 +24,7 @@ class UtilsTestCase(unittest.TestCase):
         assert json_int_dttm_ser(dttm + timedelta(milliseconds=1)) == (ts + 1)
 
         with self.assertRaises(TypeError):
-            json_int_dttm_ser("this is not a date")
+            json_int_dttm_ser('this is not a date')
 
     def test_json_iso_dttm_ser(self):
         dttm = datetime(2020, 1, 1)
@@ -35,7 +35,7 @@ class UtilsTestCase(unittest.TestCase):
         assert json_iso_dttm_ser(t) == t.isoformat()
 
         with self.assertRaises(TypeError):
-            json_iso_dttm_ser("this is not a date")
+            json_iso_dttm_ser('this is not a date')
 
     def test_base_json_conv(self):
         assert isinstance(base_json_conv(numpy.bool_(1)), bool) is True
@@ -50,7 +50,7 @@ class UtilsTestCase(unittest.TestCase):
         self.assertEquals(parse_human_timedelta('now'), timedelta(0))
 
     def test_zlib_compression(self):
-        json_str = """{"test": 1}"""
+        json_str = '{"test": 1}'
         blob = zlib_compress(json_str)
         got_str = zlib_decompress_to_string(blob)
         self.assertEquals(json_str, got_str)
diff --git a/tox.ini b/tox.ini
index 177858d..78198ea 100644
--- a/tox.ini
+++ b/tox.ini
@@ -16,9 +16,6 @@ exclude =
     superset/data
     superset/migrations
     superset/templates
-ignore =
-    Q000
-    Q001
 import-order-style = google
 max-line-length = 90
 

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