Start Behavior in Python

Hi,

I'm quite new in using Nao but I'm trying to create a python application that is starting a behaviour, e.g. the taichi-dance-free from a python script. 

Here is a code snippet:

behavior_mng_service = naoqi.ALProxy("ALBehaviorManager", self.ip, 9559)

self.getBehaviors(behavior_mng_service)
behavior_mng_service.runBehavior('taichi-dance-free')

I also tried the original code from the Documentation with the same result. It just does nothing.

Any hints what I am missing?

Best regards,