def cursorAtSpaceEnd(block):
            cursor = QTextCursor(block)
            cursor.setPosition(block.position() + len(blockIndentation(block)))
            return cursor
def test_impl(n):
            df = pd.DataFrame({'A': np.ones(n), 'B': np.random.ranf(n)})
            Ac = df.A.cumsum()
            return Ac.sum()