diff --git a/colossalai/amp/naive_amp/grad_scaler/base_grad_scaler.py b/colossalai/amp/naive_amp/grad_scaler/base_grad_scaler.py
index d27883a8e..0d84384a7 100644
--- a/colossalai/amp/naive_amp/grad_scaler/base_grad_scaler.py
+++ b/colossalai/amp/naive_amp/grad_scaler/base_grad_scaler.py
@@ -1,12 +1,14 @@
 #!/usr/bin/env python
 # -*- encoding: utf-8 -*-
 
-import torch
 from abc import ABC, abstractmethod
-from colossalai.logging import get_dist_logger
-from torch import Tensor
 from typing import Dict
 
+import torch
+from torch import Tensor
+
+from colossalai.logging import get_dist_logger
+
 __all__ = ['BaseGradScaler']