如何找出上一次python tkinter被按下的按钮

import tkinter as tk

def button_clicked(button_name):
    global last_button_clicked
    last_button_clicked = button_name

# 创建一个窗口
window = tk.Tk()

# 创建按钮并绑定回调函数
button1 = tk.Button(window, text="按钮1", command=lambda: button_clicked("按钮1"))
button1.pack()

button2 = tk.Button(window, text="按钮2", command=lambda: button_clicked("按钮2"))
button2.pack()

# 创建一个变量来存储上一次被按下的按钮
last_button_clicked = ""

# 执行窗口的主循环
window.mainloop()

# 打印上一次被按下的按钮
print("上一次被按下的按钮是：", last_button_clicked)