单链表之反转

class LNode:
    def __init__(self, x):
        self.data = x
        self.next = None

    def __repr__(self):
        return self.data

    def __str__(self):
        return str(self.data)


def Reverse(head):
    if head is None or head.next is None:
        return
    cur = head.next
    next = cur.next

    cur.next = None
    pre = cur
    cur = next
    while cur.next != None:
        next = cur.next
        cur.next = pre
        pre = cur
        cur = next
    cur.next = pre
    head.next = cur

怎么填图示？？？