当tkinter中的entrybox为空时，如何禁用它？

import tkinter as tk

def check_entrybox():
    if entrybox.get() == "":
        entrybox.config(state=tk.DISABLED)
    else:
        entrybox.config(state=tk.NORMAL)

root = tk.Tk()

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

button = tk.Button(root, text="Check", command=check_entrybox)
button.pack()

root.mainloop()