Turns on the light by gradually fading it in.
        The optional `duration` parameter allows for control
        of the fade in duration (in seconds)

def fade_in(self, duration=3, group=0):
        """Turns on the light by gradually fading it in.
        The optional `duration` parameter allows for control
        of the fade in duration (in seconds)"""
        self.on(group)
        super(WhiteLight, self).fade_in(duration, group=group)