Switch lights on. If group (1-4) is not specified,
            all four groups will be switched on.

def on(self, group=None):  # pylint: disable=invalid-name
        """ Switch lights on. If group (1-4) is not specified,
            all four groups will be switched on. """
        if group is None or group == 0:
            self._send_to_group(group, send_on=False, command="all_on")
            return
        self._send_to_group(group, per_group=True, white_cmd=self.WHITE_GROUP_X_ON, rgbw_cmd=self.RGBW_GROUP_X_ON, send_on=False)