AttributeError: 'callable_iterator' object has no attribute 'next'，python3中迭代器的next()方法已变成__next__()

报错信息：

Traceback (most recent call last):

  File "F:/unit1/01_03.py", line 149, in <module>
    g = it.next()

AttributeError: 'callable_iterator' object has no attribute 'next'

解决办法：

将上述代码中调用next()的地方全部替换为__next__()，最后在控制台运行该代码，正确得到了预期的结果