diff --git a/synapse/handlers/sliding_sync.py b/synapse/handlers/sliding_sync.py
index c216467c29..f5356cdd89 100644
--- a/synapse/handlers/sliding_sync.py
+++ b/synapse/handlers/sliding_sync.py
@@ -208,7 +208,7 @@ class SlidingSyncHandler:
                                 range=range,
                                 room_ids=[
                                     room_id
-                                    for room_id, rooms_for_user in sorted_room_info.items()[
+                                    for room_id, _ in sorted_room_info[
                                         range[0] : range[1]
                                     ]
                                 ],
diff --git a/tests/handlers/test_sliding_sync.py b/tests/handlers/test_sliding_sync.py
index 89c823fdc5..a381795971 100644
--- a/tests/handlers/test_sliding_sync.py
+++ b/tests/handlers/test_sliding_sync.py
@@ -1187,7 +1187,7 @@ class SortRoomsTestCase(HomeserverTestCase):
             (Membership.BAN,),
         ]
     )
-    def test_activity_after_xxx(self, room1_membership: Membership) -> None:
+    def test_activity_after_xxx(self, room1_membership: str) -> None:
         """
         When someone has left/been invited/knocked/been banned from a room, they
         shouldn't take anything into account after that membership event.