如何删除循环单向链表中的最后一个节点

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

def delete_last_node(head):
    if head is None:
        return None

    # 找到倒数第二个节点
    current = head
    while current.next.next != head:
        current = current.next

    # 将倒数第二个节点的next指针指向头节点
    current.next = head

    # 释放最后一个节点的内存空间
    last_node = current.next
    last_node.next = None

    return head