diff --git a/synapse/storage/user_directory.py b/synapse/storage/user_directory.py
index a15366a11..5d402189e 100644
--- a/synapse/storage/user_directory.py
+++ b/synapse/storage/user_directory.py
@@ -21,8 +21,8 @@ from six import iteritems
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, JoinRules
-from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.storage.background_updates import BackgroundUpdateStore
+from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.storage.state import StateFilter
 from synapse.types import get_domain_from_id, get_localpart_from_id
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
@@ -38,7 +38,6 @@ class UserDirectoryStore(BackgroundUpdateStore):
             "users_in_public_rooms_initial", self._populate_users_in_public_rooms
         )
 
-
     @defer.inlineCallbacks
     def _populate_users_in_public_rooms(self, progress, batch_size):
         """