'Return the class of this sensor, from DEVICE_CLASSES.'

@property
def device_class(self):

    pres = self.gateway.const.Presentation
    class_map = {pres.S_DOOR: 'opening', pres.S_MOTION: 'motion', pres.S_SMOKE: 'smoke'}
    if (float(self.gateway.protocol_version) >= 1.5):
        class_map.update({pres.S_SPRINKLER: 'sprinkler', pres.S_WATER_LEAK: 'leak', pres.S_SOUND: 'sound', pres.S_VIBRATION: 'vibration', pres.S_MOISTURE: 'moisture'})
    if (class_map.get(self.child_type) in DEVICE_CLASSES):
        return class_map.get(self.child_type)
