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.arange(n) + 1.0})
            df1 = df[df.A > 5]
            return len(df1.B)