1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index fceb9744aa..0a0691cd00 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -446,7 +446,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             room_id (str)
 
         Returns:
-            Deferred[str]: predecessor room id
+            Deferred[unicode|None]: predecessor room id
         """
         state_ids = yield self.get_current_state_ids(room_id)
         create_id = state_ids.get((EventTypes.Create, ""))