Remove redundant parentheses

Author: SabineHaas

windpowerlib/power_curves.py

@@ -104,7 +104,7 @@ def smooth_power_curve(power_curve_wind_speeds, power_curve_values,
     smoothed_power_curve_values = []
     # Append wind speeds to `power_curve_wind_speeds`
     maximum_value = power_curve_wind_speeds.values[-1] + wind_speed_range
-    while (power_curve_wind_speeds.values[-1] < maximum_value):
+    while power_curve_wind_speeds.values[-1] < maximum_value:
         power_curve_wind_speeds = power_curve_wind_speeds.append(
             pd.Series(power_curve_wind_speeds.iloc[-1] + 0.5,
                       index=[power_curve_wind_speeds.index[-1] + 1]))