Re-add docstring, with caveats detailed

2 files changed, 6 insertions, 2 deletions

diff --git a/synapse/storage/data_stores/main/group_server.py b/synapse/storage/data_stores/main/group_server.py

index 13ad71a49c..5ded539af8 100644
--- a/synapse/storage/data_stores/main/group_server.py
+++ b/synapse/storage/data_stores/main/group_server.py
@@ -552,7 +552,7 @@ class GroupServerStore(SQLBaseStore):
             keyvalues={"group_id": group_id, "role_id": role_id, "user_id": user_id},
             desc="remove_user_from_summary",
         )
-    
+
     def get_local_groups_for_room(self, room_id):
         """Get all of the local group that contain a given room
         Args:
diff --git a/synapse/storage/data_stores/main/state.py b/synapse/storage/data_stores/main/state.py

index 3132848034..a41cac7b36 100644
--- a/synapse/storage/data_stores/main/state.py
+++ b/synapse/storage/data_stores/main/state.py
@@ -285,7 +285,11 @@ class StateGroupWorkerStore(
             room_id (str)
 
         Returns:
-            Deferred[unicode|None]: predecessor room id
+            Deferred[dict|None]: A dictionary containing the structure of the predecessor
+                field from the room's create event. The structure is subject to other servers,
+                but it is expected to be:
+                    * room_id (str): The room ID of the predecessor room
+                    * event_id (str): The ID of the tombstone event in the predecessor room
 
         Raises:
             NotFoundError if the room is unknown