diff --git a/api/services/conversation_service.py b/api/services/conversation_service.py
index 1cfecd1973..bbad5fd71d 100644
--- a/api/services/conversation_service.py
+++ b/api/services/conversation_service.py
@@ -14,8 +14,8 @@ from models.account import Account
 from models.model import App, Conversation, EndUser, Message
 from services.errors.conversation import (
     ConversationNotExistsError,
-    LastConversationNotExistsError,
     ConversationVariableNotExistsError,
+    LastConversationNotExistsError,
 )
 from services.errors.message import MessageNotExistsError