def move_right_down(self, action=None, channel=0,
                        vertical_speed=1, horizontal_speed=1):
        """
        Params:
            action           - start or stop
            channel          - channel number
            vertical_speed   - range is 1-8
            horizontal_speed - range is 1-8
        """

        ret = self.command(
            'ptz.cgi?action={0}&channel={1}&code=RightDown&arg1=0'
            '&arg2={2}&arg3=0'.format(action, channel, vertical_speed)
        )
        return ret.content.decode('utf-8')
Params:
            action           - start or stop
            channel          - channel number
            vertical_speed   - range is 1-8
            horizontal_speed - range is 1-8