在树python中插入新值

class TreeNode:
    def __init__(self, value):
        self.value = value
        self.left = None
        self.right = None

def insert_node(root, value):
    if root is None:
        return TreeNode(value)
    if value < root.value:
        root.left = insert_node(root.left, value)
    else:
        root.right = insert_node(root.right, value)
    return root

# 创建树的根节点
root = None

# 插入新值到树中
root = insert_node(root, 5)
root = insert_node(root, 3)
root = insert_node(root, 7)
root = insert_node(root, 1)
root = insert_node(root, 4)
root = insert_node(root, 6)
root = insert_node(root, 8)