python Class: 面向对象高级编程 __iter__ 和 next()

官网解释：New in version 2.2.

iterator.

__iter__

()

Return the iterator object itself. This is required to allow both containers and iterators to be used with the

for

and

in

statements. This method corresponds to the

tp_iter

slot of the type structure for Python objects in the Python/C API.

iterator.

next

()

Return the next item from the container. If there are no further items, raise the

StopIteration

exception. This method corresponds to the

tp_iternext

slot of the type structure for Python objects in the Python/C API.

也就是说 __iter__与next()是配套使用的。

Fibonacci数列：
#!/usr/bin/python
# -*- coding: utf-8 -*-

class Fibo(object):
def __init__(self):
self.a, self.b = 0, 1

def __iter__(self):
return self

def __next__(self):
self.a, self.b = self.b, self.a + self.b
if self.a > 10000:
raise StopIteration()
return self.a, self.b

for n in Fibo():
print n

运行失败：


怎么用class做才能成功呢？？？？？后来，才发现，我2.7版本的解释器不支持，用网页上的Python3在线编程解释器完美运行。。。。。。is ri le gou le.附使用的python3环境：http://www.dooccn.com/python3/
请问各位大佬，在2.7版本中我该怎么使用 __iter__ 呢？？求教！！！