diff --git a/optuna_integration/keras/keras.py b/optuna_integration/keras/keras.py
index 3cf7184f..6b8c0d7c 100644
--- a/optuna_integration/keras/keras.py
+++ b/optuna_integration/keras/keras.py
@@ -3,8 +3,10 @@
 import warnings
 
 import optuna
+
 from optuna_integration._imports import try_import
 
+
 with try_import() as _imports:
     from keras.callbacks import Callback