diff --git a/src/pygama/flow/data_loader.py b/src/pygama/flow/data_loader.py
index e0c2dc0a8..7490271b0 100644
--- a/src/pygama/flow/data_loader.py
+++ b/src/pygama/flow/data_loader.py
@@ -529,7 +529,9 @@ def build_entry_list(
                             and save_output_columns
                         ):
                             for_output.append(term)
-            col_tiers_dict[level] = self.get_tiers_for_col(cut_cols[level], merge_files=False)
+            col_tiers_dict[level] = self.get_tiers_for_col(
+                cut_cols[level], merge_files=False
+            )
 
         if save_output_columns:
             entry_cols += for_output