Python gateway addon class AddOnManagerProxy

I’m trying to develop a python addon to webthings getway and have been successful so far in installing and having it appear on the things dashboard. I used the TPLink addon as a starting point. My problem is that I’m trying to capture the property changes and can’t see where to do that from. I’m trying to extend the AddonManagerProxy class and install it in the Adapter class but I get errors about number of parameters in the init function at the import line. Can anyone point me to any material on how to get this done.