1 files changed, 7 insertions, 4 deletions
diff --git a/synapse/storage/databases/main/push_rule.py b/synapse/storage/databases/main/push_rule.py
index fa782023d4..3b63267395 100644
--- a/synapse/storage/databases/main/push_rule.py
+++ b/synapse/storage/databases/main/push_rule.py
@@ -28,7 +28,10 @@ from synapse.storage.databases.main.receipts import ReceiptsWorkerStore
 from synapse.storage.databases.main.roommember import RoomMemberWorkerStore
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.storage.push_rule import InconsistentRuleException, RuleNotFoundException
-from synapse.storage.util.id_generators import StreamIdGenerator
+from synapse.storage.util.id_generators import (
+    AbstractStreamIdTracker,
+    StreamIdGenerator,
+)
 from synapse.util import json_encoder
 from synapse.util.caches.descriptors import cached, cachedList
 from synapse.util.caches.stream_change_cache import StreamChangeCache
@@ -82,9 +85,9 @@ class PushRulesWorkerStore(
         super().__init__(database, db_conn, hs)
 
         if hs.config.worker.worker_app is None:
-            self._push_rules_stream_id_gen: Union[
-                StreamIdGenerator, SlavedIdTracker
-            ] = StreamIdGenerator(db_conn, "push_rules_stream", "stream_id")
+            self._push_rules_stream_id_gen: AbstractStreamIdTracker = StreamIdGenerator(
+                db_conn, "push_rules_stream", "stream_id"
+            )
         else:
             self._push_rules_stream_id_gen = SlavedIdTracker(
                 db_conn, "push_rules_stream", "stream_id"