python链表的乘法问题

   def __mul__(self, other):

        if type(other) is Node:

            n1,n2 = self.values,other.values

            product = [p[0]*p[1] for p in zip(n1,n2)]

            return Node.build(product)

        if other<0 or type(other) is not int:

            raise TypeError("other is a non-negetive Integer")

        if other==0:return Node()

        ret = self.copy()

        for _ in range(1,other):

            self += ret

        return self

    __rmul__ = __mul__

'''

>>> a = Node() + range(1,3)

>>> a * 0

Node(None->None)

>>> a * 1

Node(1->2->None)

>>> a * 2

Node(1->2->1->2->None)

>>> a * 5

Node(1->2->1->2->1->2->1->2->1->2->None)

>>>

>>> 3 * a

Node(1->2->1->2->1->2->None)

>>> a

Node(1->2->None)

>>> a *= 5

>>> a

Node(1->2->1->2->1->2->1->2->1->2->None)

>>>

>>>

>>> a = Node() + range(1,8)

>>> b = Node(2) * 7

>>> a * b

Node(2->4->6->8->10->12->14->None)

>>> b * a

Node(2->4->6->8->10->12->14->None)

>>>

'''