def test_type(self):
        rset = event.ResultSet()
        with pytest.raises(NotImplementedError):
            rset.extend([])
        with pytest.raises(NotImplementedError):
            rset.extend(False)
def test_strictly_between():
    """Greater than y and less than z."""
    p = are.strictly_between(2, 4)
    ps = [p(x) for x in range(1, 6)]
    assert ps == [False, False, True, False, False]