当toplevel关闭时如何关闭整个GUI

import tkinter as tk

def close_gui():
    # 关闭所有子窗口和相关组件
    for child in root.winfo_children():
        child.destroy()
    # 销毁主窗口
    root.destroy()

def create_child_window():
    # 创建子窗口
    child_window = tk.Toplevel(root)
    child_window.title("子窗口")
    child_window.geometry("200x200")
    child_window.protocol("WM_DELETE_WINDOW", close_gui)

root = tk.Tk()
root.title("主窗口")
root.geometry("400x400")

# 创建按钮，用于打开子窗口
open_button = tk.Button(root, text="打开子窗口", command=create_child_window)
open_button.pack()

# 主窗口关闭事件
root.protocol("WM_DELETE_WINDOW", close_gui)

root.mainloop()