如何在Python中用tkinter检查多项选择(复选框)？

import tkinter as tk

root = tk.Tk()
checkbox1 = tk.Checkbutton(root, text="选项1")
checkbox2 = tk.Checkbutton(root, text="选项2")
checkbox3 = tk.Checkbutton(root, text="选项3")

checkbox1.select()  # 默认选中
checkbox2.deselect()  # 默认不选中
checkbox3.deselect()  # 默认不选中

checkbox1.pack()
checkbox2.pack()
checkbox3.pack()

def check_selection():
    if checkbox1.instate(['selected']):
        print("选项1被选中")
    if checkbox2.instate(['selected']):
        print("选项2被选中")
    if checkbox3.instate(['selected']):
        print("选项3被选中")

button = tk.Button(root, text="检查选择", command=check_selection)
button.pack()

root.mainloop()