1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/visibility.py b/synapse/visibility.py
index c64ad2144c..43f48196be 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -219,7 +219,7 @@ def filter_events_for_server(store, server_name, events):
     # Whatever else we do, we need to check for senders which have requested
     # erasure of their data.
     erased_senders = yield store.are_users_erased(
-        e.sender for e in events,
+        (e.sender for e in events),
     )
 
     def redact_disallowed(event, state):