以下代码让我困惑:
>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> zip(*([iter(a)]*2))
[(0, 1), (2, 3), (4, 5), (6, 7), (8, 9)]
>>> iter(a)
<listiterator object at 0x7f3e9920cf50>
>>> iter(a).next()
0
>>> iter(a).next()
0
>>> iter(a).next()
0
next()总是返回0.那么,该iter功能如何工作？