diff --git a/setup.py b/setup.py
index 0332ed4..c6a454a 100644
--- a/setup.py
+++ b/setup.py
@@ -47,16 +47,16 @@ def get_version():
 
 
 setup(
-    name="wcs-olap",
+    name='wcs-olap',
     version=get_version(),
-    license="AGPLv3+",
-    description="Export w.c.s. data to an OLAP cube",
+    license='AGPLv3+',
+    description='Export w.c.s. data to an OLAP cube',
     long_description=open('README.rst').read(),
-    url="http://dev.entrouvert.org/projects/publik-bi/",
+    url='http://dev.entrouvert.org/projects/publik-bi/',
     author="Entr'ouvert",
-    author_email="authentic@listes.entrouvert.com",
-    maintainer="Benjamin Dauvergne",
-    maintainer_email="bdauvergne@entrouvert.com",
+    author_email='authentic@listes.entrouvert.com',
+    maintainer='Benjamin Dauvergne',
+    maintainer_email='bdauvergne@entrouvert.com',
     packages=find_packages(),
     include_package_data=True,
     install_requires=['requests', 'psycopg2', 'isodate', 'six', 'cached-property'],
diff --git a/tests/test_wcs.py b/tests/test_wcs.py
index 4cb3a5e..18cbcf2 100644
--- a/tests/test_wcs.py
+++ b/tests/test_wcs.py
@@ -216,7 +216,7 @@ def test_requests_exception(wcs, postgres_db, tmpdir, olap_cmd, caplog):
 def test_requests_not_ok(wcs, postgres_db, tmpdir, olap_cmd, caplog):
     @httmock.urlmatch()
     def return_401(url, request):
-        return {'status_code': 401, 'content': {"err": 1, "err_desc": "invalid signature"}}
+        return {'status_code': 401, 'content': {'err': 1, 'err_desc': 'invalid signature'}}
 
     with httmock.HTTMock(return_401):
         assert olap_cmd(no_log_errors=False) != 0
diff --git a/wcs_olap/cmd.py b/wcs_olap/cmd.py
index 3ab6c1f..c4314a6 100644
--- a/wcs_olap/cmd.py
+++ b/wcs_olap/cmd.py
@@ -91,7 +91,7 @@ def main2():
     )
     parser.add_argument('--no-log-errors', dest='no_log_errors', action='store_true', default=False)
     parser.add_argument('--fake', action='store_true', default=False)
-    group.add_argument("-a", "--all", help="synchronize all wcs", action='store_true', default=False)
+    group.add_argument('-a', '--all', help='synchronize all wcs', action='store_true', default=False)
     group.add_argument('--url', help='url of the w.c.s. instance', required=False, default=None)
     args, rest = parser.parse_known_args()
     feed = args.feed
@@ -110,7 +110,7 @@ def main2():
         urls = [url]
         if config.has_section(args.url):
             defaults = dict(config.items(args.url))
-        parser.add_argument("-h", "--help", action="help", help="show this help message and exit")
+        parser.add_argument('-h', '--help', action='help', help='show this help message and exit')
         parser.add_argument('--orig', help='origin of the request for signatures')
         parser.add_argument('--slug', action='append', default=[])
         parser.add_argument('--key', help='HMAC key for signatures')
diff --git a/wcs_olap/feeder.py b/wcs_olap/feeder.py
index 850198c..b199795 100644
--- a/wcs_olap/feeder.py
+++ b/wcs_olap/feeder.py
@@ -278,7 +278,7 @@ class WcsOlapFeeder:
                     'name': 'percent',
                     'label': 'pourcentage des demandes',
                     'type': 'percent',
-                    "expression": 'case (select count({fact_table}.id) from {table_expression} '
+                    'expression': 'case (select count({fact_table}.id) from {table_expression} '
                     'where {where_conditions}) when 0 then null else '
                     'count({fact_table}.id) * 100. / (select '
                     'count({fact_table}.id) from {table_expression} where '
@@ -391,8 +391,8 @@ class WcsOlapFeeder:
         """
         # drop foreign key constraints first
         self.ex(
-            "SELECT table_name, constraint_name FROM "
-            "information_schema.key_column_usage "
+            'SELECT table_name, constraint_name FROM '
+            'information_schema.key_column_usage '
             "WHERE table_schema = %s AND constraint_name LIKE '%%_fkey'",
             vars=[schema],
         )
@@ -405,9 +405,9 @@ class WcsOlapFeeder:
                 )
         # remove others
         self.ex(
-            "SELECT table_name, constraint_name FROM "
-            "information_schema.key_column_usage "
-            "WHERE table_schema = %s",
+            'SELECT table_name, constraint_name FROM '
+            'information_schema.key_column_usage '
+            'WHERE table_schema = %s',
             vars=[schema],
         )
         for table_name, constraint_name in self.cur.fetchall():
@@ -418,14 +418,14 @@ class WcsOlapFeeder:
                     % (quote(schema), quote(table_name), quote(constraint_name))
                 )
         # then drop indexes
-        self.ex("SELECT tablename, indexname FROM pg_indexes WHERE schemaname = %s", vars=[schema])
+        self.ex('SELECT tablename, indexname FROM pg_indexes WHERE schemaname = %s', vars=[schema])
         for table_name, index_name in self.cur.fetchall():
             with ignore_undefined_object_or_table():
                 self.ex('DROP INDEX %s.%s CASCADE' % (quote(schema), quote(index_name)))
 
         # finally drop tables, cascade will have no effect
         self.ex(
-            "SELECT tablename FROM pg_tables WHERE schemaname = %s ORDER BY tablename DESC", vars=[schema]
+            'SELECT tablename FROM pg_tables WHERE schemaname = %s ORDER BY tablename DESC', vars=[schema]
         )
         for table in self.cur.fetchall():
             tablename = '%s.%s' % (quote(schema), quote(table[0]))