tkinter -单选按钮未设置默认结果

import tkinter as tk

root = tk.Tk()

# 创建IntVar变量来跟踪选择的值
selected_option = tk.IntVar()

# 创建单选按钮，设置variable为selected_option，并设置value为选项的值
option1 = tk.Radiobutton(root, text="Option 1", variable=selected_option, value=1)
option2 = tk.Radiobutton(root, text="Option 2", variable=selected_option, value=2)
option3 = tk.Radiobutton(root, text="Option 3", variable=selected_option, value=3)

# 默认选中一个选项
selected_option.set(1)

# 显示单选按钮
option1.pack()
option2.pack()
option3.pack()

root.mainloop()