diff --git a/windpowerlib/power_output.py b/windpowerlib/power_output.py
index 684009f..8b1425e 100644
--- a/windpowerlib/power_output.py
+++ b/windpowerlib/power_output.py
@@ -236,7 +236,7 @@ def power_curve_density_correction(
             + "height is needed."
         )
 
-    # Convert pandas.Series to a numpy array to speed up the interpolation below.    
+    # Convert pandas.Series to a numpy array to speed up the interpolation below.
     if isinstance(wind_speed, pd.Series):
         # save the indexes for later conversion to pd.Series
         wind_speed_indexes = wind_speed.index
@@ -267,7 +267,9 @@ def power_curve_density_correction(
     ]
 
     # Power_output as pd.Series if wind_speed is pd.Series (else: np.array)
-    if panda_series:  # use the flag to check if the data should be converted back to pandas.Series
+    if (
+        panda_series
+    ):  # use the flag to check if the data should be converted back to pandas.Series
         power_output = pd.Series(
             data=power_output,
             index=wind_speed_indexes,  # Use previously saved wind speed indexes