class LaserDistance(ReadonlyRegisterBase):
    def __init__(self):
        ReadonlyRegisterBase.__init__(self, "laser_distance")
        
    def doRead(self):
        ret = ue.readable.read()
        ret = None if ret is None else (0.0 if math.isnan(ret) else ret)
        return ret

class ListenerAI (DeviceListener):
    def onValueChanged(self, device, value, former):        
        if laser_distance is not None:                    
            value = None if value is None else (0.0 if math.isnan(value) else value)                        
            laser_distance.setCache(value, None)            


for l in ue.listeners:
    if Nameable.getShortClassName(l.getClass()) == "ListenerAI":
        ue.removeListener(l)


listenerAI = ListenerAI()
ue.addListener(listenerAI)
        
laser_distance=LaserDistance()   
add_device(laser_distance, True)
laser_distance.update()