diff --git a/monai/networks/blocks/selfattention.py b/monai/networks/blocks/selfattention.py
index 29a818c34f..86e1b1d3ae 100644
--- a/monai/networks/blocks/selfattention.py
+++ b/monai/networks/blocks/selfattention.py
@@ -11,7 +11,7 @@
 
 from __future__ import annotations
 
-from typing import Tuple, Union, Optional
+from typing import Optional, Tuple, Union
 
 import torch
 import torch.nn as nn