diff --git a/src/demandlib/bdew/elec_slp.py b/src/demandlib/bdew/elec_slp.py
index e8e5426..ee9d9e9 100644
--- a/src/demandlib/bdew/elec_slp.py
+++ b/src/demandlib/bdew/elec_slp.py
@@ -116,9 +116,9 @@ def create_bdew_load_profiles(self, dt_index, slp_types, holidays=None):
             new_df, holidays=holidays, holiday_is_sunday=True
         )
 
-        new_df["hour"] = dt_index.hour.astype('int64')
-        new_df["weekday"] = new_df["weekday"].astype('int64')
-        new_df["minute"] = dt_index.minute.astype('int64')
+        new_df["hour"] = dt_index.hour.astype("int64")
+        new_df["weekday"] = new_df["weekday"].astype("int64")
+        new_df["minute"] = dt_index.minute.astype("int64")
         time_df = new_df[["date", "hour", "minute", "weekday"]].copy()
         tmp_df[slp_types] = tmp_df[slp_types].astype(float)