def get_led_register_from_name(self, name):
        """Parse the name for led number

        :param name: attribute name, like: led_1
        """
        res = re.match('^led_([0-9]{1,2})$', name)
        if res is None:
            raise AttributeError("Unknown attribute: '%s'" % name)
        led_num = int(res.group(1))
        if led_num < 0 or led_num > 15:
            raise AttributeError("Unknown attribute: '%s'" % name)
        return self.calc_led_register(led_num)
Parse the name for led number

        :param name: attribute name, like: led_1