Configure stepper motor prior to operation.
        This is a FirmataPlus feature.

        :param steps_per_revolution: number of steps per motor revolution

        :param stepper_pins: a list of control pin numbers - either 4 or 2

        :returns: No return value

def stepper_config(self, steps_per_revolution, stepper_pins):
        """
        Configure stepper motor prior to operation.
        This is a FirmataPlus feature.

        :param steps_per_revolution: number of steps per motor revolution

        :param stepper_pins: a list of control pin numbers - either 4 or 2

        :returns: No return value

        """
        task = asyncio.ensure_future(self.core.stepper_config(steps_per_revolution,
                                                              stepper_pins))
        self.loop.run_until_complete(task)