diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 2d16094823..79ae6651a6 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -753,7 +753,11 @@ class RoomCreationHandler(BaseHandler):
                 power_level_content.update(power_level_content_override)
 
             if creator_id not in power_level_content["users"]:
-                raise SynapseError(400, "Not a valid power_level_content_override, did not contain %s" % (creator_id,))
+                raise SynapseError(
+                    400,
+                    "Not a valid power_level_content_override, did not contain %s"
+                    % (creator_id,)
+                )
 
             yield send(etype=EventTypes.PowerLevels, content=power_level_content)