如何在tkinter中检查单选按钮是否被选中但输入框为空？

import tkinter as tk

def check_selection():
    if selected.get() == 1 and entry.get() == "":
        print("单选按钮被选中且输入框为空")
        # 执行相应的操作

root = tk.Tk()

selected = tk.IntVar()

radio = tk.Radiobutton(root, text="选项1", variable=selected, value=1)
radio.pack()

entry = tk.Entry(root)
entry.pack()

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

root.mainloop()