如何在循环链表中插入字符串(我想在循环链表中检查重复的单词)？

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

def insert_word(head, word):
    if head is None:
        new_node = Node(word)
        new_node.next = new_node  # 形成循环链表
        return new_node

    current = head
    while current.next != head:
        if current.data == word:
            return head  # 存在重复单词，直接返回原链表
        current = current.next

    if current.data == word:
        return head  # 存在重复单词，直接返回原链表

    new_node = Node(word)
    new_node.next = head
    current.next = new_node
    return new_node

# 创建循环链表
head = None
words = ["apple", "banana", "cherry", "apple", "date"]
for word in words:
    head = insert_word(head, word)

# 打印循环链表
current = head
while True:
    print(current.data)
    current = current.next
    if current == head:
        break