A strange question, In "onChanged" function The change of list data is invalid！？

[openBrain]

The difference between the 2 objects was not clear to me either, at the beginning.
And I think a big part of my confusion was because of this strange use of __init__()

Yep you're right. Maybe a complete example would include 2 classes. One for the object, and one for the proxy.
Anyway, many thanks for sharing this highly useful snippet.