Bugbear: Add Mutable Parameter fixes (#9682)

Part of #9366

Adds in fixes for B006 and B008, both relating to mutable parameter lint errors.

Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>

1 files changed, 3 insertions, 1 deletions

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

index 8f462dfc31..bd7826f4e9 100644
--- a/synapse/storage/databases/main/group_server.py
+++ b/synapse/storage/databases/main/group_server.py
@@ -1171,7 +1171,7 @@ class GroupServerStore(GroupServerWorkerStore):
         user_id: str,
         membership: str,
         is_admin: bool = False,
-        content: JsonDict = {},
+        content: Optional[JsonDict] = None,
         local_attestation: Optional[dict] = None,
         remote_attestation: Optional[dict] = None,
         is_publicised: bool = False,
@@ -1192,6 +1192,8 @@ class GroupServerStore(GroupServerWorkerStore):
             is_publicised: Whether this should be publicised.
         """
 
+        content = content or {}
+
         def _register_user_group_membership_txn(txn, next_id):
             # TODO: Upsert?
             self.db_pool.simple_delete_txn(