diff --git a/qlib/data/filter.py b/qlib/data/filter.py
index 784fad8d7..d2e5aa901 100644
--- a/qlib/data/filter.py
+++ b/qlib/data/filter.py
@@ -354,7 +354,7 @@ class ExpressionDFilter(SeriesDFilter):
         rule_expression_field_name = list(_features.keys())[0]
         all_filter_series = _features[rule_expression_field_name]
         return all_filter_series
-    
+
     @staticmethod
     def from_config(config):
         return ExpressionDFilter(