diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 0676e7f626e6..67b15697fd39 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -317,7 +317,9 @@ def clone_existing_room(
         )
 
         # map from event_id to BaseEvent
-        old_room_member_state_events = yield self.store.get_events(old_room_member_state_ids.values())
+        old_room_member_state_events = yield self.store.get_events(
+            old_room_member_state_ids.values(),
+        )
         for k, old_event in iteritems(old_room_member_state_events):
             # Only transfer ban events
             if ("membership" in old_event.content and