program can not raise python error message normally

[wuwao1]

hello ,can someone help look this question
I wrapped a Windows form, below is my wrapping project:
minimun_case.zip

in the issue_case.py script,the following code can throw a Python exception normally

    def GetWindowClassName(self):        
        x=y    # can throw a Python exception normally
        print("GetWindowClassName")
        return "CWindowWndInherite"

__init__
NameError: name 'y' is not defined

At:
  E:\z\minimun_case\Example\lib\issue_case.py(12): GetWindowClassName
  E:\z\minimun_case\Example\lib\issue_case.py(22): <module>
  <frozen importlib._bootstrap>(241): _call_with_frames_removed
  <frozen importlib._bootstrap_external>(883): exec_module
  <frozen importlib._bootstrap>(703): _load_unlocked
  <frozen importlib._bootstrap>(1006): _find_and_load_unlocked
  <frozen importlib._bootstrap>(1027): _find_and_load

However, the following code cannot throw a Python exception

    def HandleMessage(self,uMsg,wParam,lParam):        
        x=y    # cannot throw a Python exception
        print("HandleMessage")
        return issue_case_wnd.HandleMessage(self,uMsg,wParam,lParam)

Is there something I'm missing? Can anyone offer some advice? Thank you in advance.

[wuwao1]

add try...catch... in cpp source code and now it work well.