code: def refresh_keyboard_mapping(self, evt):
          
          if isinstance(evt, event.MappingNotify):
              if evt.request == X.MappingKeyboard:
                  self._update_keymap(evt.first_keycode, evt.count)
          else:
              raise TypeError('expected a MappingNotify event')
docs: This method should be called once when a MappingNotify event
          is received, to update the keymap cache. evt should be the event
          object.