fix: check types

Author: GefMar

taskiq/middlewares/smart_retry_middleware.py

@@ -3,6 +3,7 @@
 import datetime
 import random
 from logging import getLogger
+from types import NoneType
 from typing import Any
 
 from taskiq import ScheduleSource
@@ -61,10 +62,7 @@ def __init__(
         self.max_delay_exponent = max_delay_exponent
         self.schedule_source = schedule_source
 
-        if schedule_source is not None and not isinstance(
-            schedule_source,
-            ScheduleSource,
-        ):
+        if not isinstance(schedule_source, (ScheduleSource, NoneType)):
             raise TypeError(
                 "schedule_source must be an instance of ScheduleSource or None",
             )