diff --git a/synapse/storage/databases/main/events_worker.py b/synapse/storage/databases/main/events_worker.py

index 6d0ef10258..20b7a68362 100644
--- a/synapse/storage/databases/main/events_worker.py
+++ b/synapse/storage/databases/main/events_worker.py
@@ -72,7 +72,6 @@ from synapse.storage.engines import PostgresEngine
 from synapse.storage.types import Cursor
 from synapse.storage.util.id_generators import (
     AbstractStreamIdGenerator,
-    AbstractStreamIdTracker,
     MultiWriterIdGenerator,
     StreamIdGenerator,
 )
@@ -187,8 +186,8 @@ class EventsWorkerStore(SQLBaseStore):
     ):
         super().__init__(database, db_conn, hs)
 
-        self._stream_id_gen: AbstractStreamIdTracker
-        self._backfill_id_gen: AbstractStreamIdTracker
+        self._stream_id_gen: AbstractStreamIdGenerator
+        self._backfill_id_gen: AbstractStreamIdGenerator
         if isinstance(database.engine, PostgresEngine):
             # If we're using Postgres than we can use `MultiWriterIdGenerator`
             # regardless of whether this process writes to the streams or not.
@@ -1493,7 +1492,7 @@ class EventsWorkerStore(SQLBaseStore):
 
             txn.execute(redactions_sql + clause, args)
 
-            for (redacter, redacted) in txn:
+            for redacter, redacted in txn:
                 d = event_dict.get(redacted)
                 if d:
                     d.redactions.append(redacter)