1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/notifier.py b/synapse/notifier.py
index d35c1f3f02..c178db57e3 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -548,7 +548,7 @@ class Notifier:
         pagination_config: PaginationConfig,
         timeout: int,
         is_guest: bool = False,
-        explicit_room_id: str = None,
+        explicit_room_id: Optional[str] = None,
     ) -> EventStreamResult:
         """For the given user and rooms, return any new events for them. If
         there are no new events wait for up to `timeout` milliseconds for any