Returns the maximum value that is accepted by the `speed_sp` attribute. This
        may be slightly different than the maximum speed that a particular motor can
        reach - it's the maximum theoretical speed.

def max_speed(self):
        """
        Returns the maximum value that is accepted by the `speed_sp` attribute. This
        may be slightly different than the maximum speed that a particular motor can
        reach - it's the maximum theoretical speed.
        """
        (self._max_speed, value) = self.get_cached_attr_int(self._max_speed, 'max_speed')
        return value