diff --git a/user_behavior_analysis/data_preparation.py b/user_behavior_analysis/data_preparation.py
index d4ba0d266..ec5d74c6e 100644
--- a/user_behavior_analysis/data_preparation.py
+++ b/user_behavior_analysis/data_preparation.py
@@ -1,5 +1,6 @@
 import pandas as pd
 
+
 class DataPreparation:
     def __init__(self, data_file):
         self.data_file = data_file