diff --git a/dargs/dargs.py b/dargs/dargs.py
index 5058bcd..dc70b0d 100644
--- a/dargs/dargs.py
+++ b/dargs/dargs.py
@@ -25,6 +25,7 @@
 from enum import Enum
 from textwrap import indent
 from typing import Any, Callable, Dict, Iterable, List, Optional, Union
+
 try:
     from typing import get_origin
 except ImportError: