I'm trying to implement the interface of IWin32Window, so that when the UI from PythonDotNet is created, I can set the owner. Here is the code, class WindowWrapper(System.Windows.Forms.IWin32Window): def __init__(self, handle): self._hwnd = handle def Handle(): doc = "property foo's doc string" def fget(self): return self._hwnd return locals() Handle = property(**Handle()) However, when an instance of WindowWrapper gets created, I got the following error---# TypeError: object does not implement IWin32Window # Here is the code to create an instance of WindowWrapper procs = System.Diagnostics.Process.GetProcessesByName("maya"); intPtr = procs[0].MainWindowHandle self.winWrapper = WindowWrapper(intPtr) It seems I am doing something wrong in class WindowWrapper...