1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py
index eedde97ab0..7c62cdfaef 100644
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@@ -1538,7 +1538,7 @@ class FederationEventHandler:
             logger.exception("Failed to resync device for %s", sender)
 
     async def backfill_event_id(
-        self, destinations: List[str], room_id: str, event_id: str
+        self, destinations: StrCollection, room_id: str, event_id: str
     ) -> PulledPduInfo:
         """Backfill a single event and persist it as a non-outlier which means
         we also pull in all of the state and auth events necessary for it.