def test_type(self):
        rset = event.ResultSet()
        with pytest.raises(NotImplementedError):
            rset.extend([])
        with pytest.raises(NotImplementedError):
            rset.extend(False)
def EVT_MOUSEWHEEL(event):
  global zoomdist
  dy = event.WheelRotation
  zoomdist *= np.power(0.95, -dy)
  refresh()