code: def _register_hid_notification(self):
          
          # create structure, self initialized
          notify_obj = DevBroadcastDevInterface()
          h_notify = RegisterDeviceNotification(self.__hid_hwnd,
                  ctypes.byref(notify_obj), DEVICE_NOTIFY_WINDOW_HANDLE)
          #
          return int(h_notify)
docs: Register HID notification events on any window (passed by window
          handler), returns a notification handler