如何使用2个LinkedLlsts重载+=

class LinkedList:
    def __init__(self):
        self.head = None

    def append(self, data):
        new_node = Node(data)
        if self.head is None:
            self.head = new_node
        else:
            current = self.head
            while current.next:
                current = current.next
            current.next = new_node

    def __iadd__(self, other):
        current = other.head
        while current:
            self.append(current.data)
            current = current.next
        return self

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

# 创建两个LinkedLists
list1 = LinkedList()
list2 = LinkedList()

# 向list1中添加元素
list1.append(1)
list1.append(2)
list1.append(3)

# 向list2中添加元素
list2.append(4)
list2.append(5)
list2.append(6)

# 使用+=操作符将list2的元素添加到list1中
list1 += list2

# 打印合并后的list1
current = list1.head
while current:
    print(current.data)
    current = current.next