sensor wrapper

[jsnider]

Hi,
I want to wrap an interface around a sensor plugin. I've done it before with a CustomObject ( derive from viz.CustomChild and use viz.upgradeCustomNode ...), and that works great. It looks like the same thing should work for a VizSensor object, but on the following it won't let me call the functions in the derived class (testCall).

import viz

class SensorClass(viz.VizSensor):
	def testCall(self):
		self.command(1, '', 1)
		
viz.upgradeSensor('sensor.dls',SensorClass)
def addMySensor():
	return viz.add('sensor.dls')
	
if __name__ == '__main__':
	viz.go()
	
	S1 = addMySensor()
	ball = viz.add('ball.wrl')
	viz.link(S1, ball)

	S1.testCall()

sensor.dls is just the sample sensor from the SDK and it works fine (the ball moves around in a circle), but the call to testCall throws an error:
AttributeError: 'VizSensor' object has no attribute 'testCall'
Is there a way to get access to the functions I define in the derived class?
Thanks,
Joe