如何在选择后插入节点？

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

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

    def insert_after(self, prev_node, new_data):
        if prev_node is None:
            print("Previous node must be in the Linked List.")
            return

        new_node = Node(new_data)
        new_node.next = prev_node.next
        prev_node.next = new_node

    def print_list(self):
        current_node = self.head
        while current_node:
            print(current_node.data)
            current_node = current_node.next

# 创建链表
linked_list = LinkedList()

# 插入节点
node1 = Node("Node 1")
linked_list.head = node1

node2 = Node("Node 2")
node1.next = node2

node3 = Node("Node 3")
node2.next = node3

# 在选择后插入节点
new_node = Node("New Node")
linked_list.insert_after(node2, new_node)

# 打印链表
linked_list.print_list()