This method activates a stepper motor motion.
        This is a FirmataPlus feature.
        :param command: {"method": "stepper_step", "params": [SPEED, NUMBER_OF_STEPS]}
        :returns:No message returned.

async def stepper_step(self, command):
        """
        This method activates a stepper motor motion.
        This is a FirmataPlus feature.
        :param command: {"method": "stepper_step", "params": [SPEED, NUMBER_OF_STEPS]}
        :returns:No message returned.
        """
        speed = int(command[0])
        num_steps = int(command[1])
        await self.core.stepper_step(speed, num_steps)