def test_type(self):
        rset = event.ResultSet()
        with pytest.raises(NotImplementedError):
            rset.extend([])
        with pytest.raises(NotImplementedError):
            rset.extend(False)
def test_impl(n):
            df = pd.DataFrame({'A': np.arange(n), 'B': np.random.ranf(n)})
            Ac = df.A.rolling(3).sum()
            return Ac.sum()