diff --git a/mirai_extensions/trigger/filter.py b/mirai_extensions/trigger/filter.py
index acde705..0f8dd55 100644
--- a/mirai_extensions/trigger/filter.py
+++ b/mirai_extensions/trigger/filter.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 from typing import (
-    Any, Callable, Generic, Iterable, List, Optional, Type, TypeVar, Union
+    Any, Callable, Generic, Iterable, List, Optional, Type, TypeVar
 )
 
 TEvent = TypeVar('TEvent')
diff --git a/mirai_extensions/trigger/message.py b/mirai_extensions/trigger/message.py
index 05d50a2..532887f 100644
--- a/mirai_extensions/trigger/message.py
+++ b/mirai_extensions/trigger/message.py
@@ -8,7 +8,6 @@
     FriendMessage, GroupMessage, MessageEvent, TempMessage
 )
 from mirai.models.message import MessageChain, Quote
-from mirai.utils import async_
 from mirai_extensions.trigger.filter import BaseFilter, TFilter, Filter
 
 logger = logging.getLogger(__name__.replace('mirai_extensions', 'mirai'))