def test_type(self):
        rset = event.ResultSet()
        with pytest.raises(NotImplementedError):
            rset.extend([])
        with pytest.raises(NotImplementedError):
            rset.extend(False)
def warn(txt, act, opt):
    if opt.get('display_examples'):
        print(txt + ":\n" + str(act))
    else:
        warn_once(txt)