1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/util/caches/stream_change_cache.py b/synapse/util/caches/stream_change_cache.py
index 3a41a8baa6..27b1da235e 100644
--- a/synapse/util/caches/stream_change_cache.py
+++ b/synapse/util/caches/stream_change_cache.py
@@ -195,7 +195,7 @@ class StreamChangeCache:
             for entity in r:
                 del self._entity_to_key[entity]
 
-    def _evict(self):
+    def _evict(self) -> None:
         while len(self._cache) > self._max_size:
             k, r = self._cache.popitem(0)
             self._earliest_known_stream_pos = max(k, self._earliest_known_stream_pos)