class Node:
def __init__(self, data):
self.data = data
self.prev = None
self.next = None
# 作业：双链表节点的创建（尾插法）
def creat_double_tail_listlink(lis): #传进来一个列表参数
head = Node(0)
ayue = head
for i in lis:
node = Node(i)
ayue.next = node
node.prev = ayue
ayue = node
head = head.next
return head
link = creat_double_tail_listlink([1,2,3,4])
print(link.next.prev.data)
