def cursorAtSpaceEnd(block):
            cursor = QTextCursor(block)
            cursor.setPosition(block.position() + len(blockIndentation(block)))
            return cursor
def test_impl(n):
            df = pd.DataFrame({'A': np.arange(n)})
            df['B'] = df.A.map(lambda a: 2 * a)
            return df.B.sum()