diff --git a/colossalai/engine/gradient_handler/_base_gradient_handler.py b/colossalai/engine/gradient_handler/_base_gradient_handler.py
index 0c1309898..c21235986 100644
--- a/colossalai/engine/gradient_handler/_base_gradient_handler.py
+++ b/colossalai/engine/gradient_handler/_base_gradient_handler.py
@@ -12,6 +12,7 @@ class BaseGradientHandler(ABC):
         model (Module): Model where the gradients accumulate.
         optimizer (Optimizer): Optimizer for updating the parameters.
     """
+
     def __init__(self, model, optimizer):
         self._model = model
         self._optimizer = optimizer
diff --git a/colossalai/engine/ophooks/_base_ophook.py b/colossalai/engine/ophooks/_base_ophook.py
index e948a8cfb..24251141d 100644
--- a/colossalai/engine/ophooks/_base_ophook.py
+++ b/colossalai/engine/ophooks/_base_ophook.py
@@ -5,6 +5,7 @@ import torch
 class BaseOpHook(ABC):
     """This class allows users to add customized operations
     before and after the execution of a PyTorch submodule"""
+
     def __init__(self):
         pass