I've fixed the crash bug and added a couple of tests (see PR #196, already
merged into develop).
For an example of how to implement an event declared on an interface see
testEvents in src/tests/test_subclass.py. Note that it's a pretty simple
implementation and isn't thread safe so may need modify
New update:
I found why the stackoverflow happened, and how to avoid it and make MVVM model
work. however, it did not entirely solve the problem.
The StackOverFlow was not directly because of the INotifyPropertyChanged
interface, but because I used a class derived from it.
if I define my ViewMode
