list--pop()

发现一个神奇的问题：

>>> list = range(101)

　>>> type(list)
　<class 'range'>

>>> list = [1,2,3]
>>> type(list)
<class 'list'>
>>> list
[1, 2, 3]
>>> list.pop(a)
2
>>> list.pop(a)
3
>>> list.pop(a)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: pop index out of range
>>> list.pop(0)
1
>>> list
[]
>>> list.pop(0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: pop from empty list
>>>

1.range()生成的不是list类型，而是range类型

2.pop()应该是弹出对应下标的元素啊？怎么pop(a)像是等价于pop(1)呢？