fix lint

Author: richvdh

synapse/storage/databases/main/end_to_end_keys.py

@@ -1453,14 +1453,17 @@ def impl(txn: LoggingTransaction) -> Tuple[bool, Optional[int]]:
             impl,
         )
 
-    async def delete_old_otks_for_one_user(self, after_user_id: str) -> Tuple[Optional[str], int]:
+    async def delete_old_otks_for_one_user(
+        self, after_user_id: str
+    ) -> Tuple[Optional[str], int]:
         """Deletes old OTKs belonging to one user.
 
         Returns:
             `(user, rows)`, where:
              * `user` is the user ID of the updated user, or None if we are don
              * `rows` is the number of deleted rows
         """
+
         def impl(txn: LoggingTransaction) -> Tuple[Optional[str], int]:
             # Find the next user
             txn.execute(