def test_type(self):
        rset = event.ResultSet()
        with pytest.raises(NotImplementedError):
            rset.extend([])
        with pytest.raises(NotImplementedError):
            rset.extend(False)
def patkind(pattern, default=None):
    """If pattern is 'kind:pat' with a known kind, return kind."""
    return _patsplit(pattern, default)[0]