写了段代码，想在按下button的时候跳个提示框出来，调试的时候提示了messagebox未定义
from tkinter import *
def test_show():
messagebox.showinfo(None, 'first')
root = Tk()
one = Label(root, text = 'First')
one.pack()
two = Button(root, text = 'First', command=test_show)
two.pack()
mainloop()
而后在CSDN上看到有人说messagebox输入子模块，不会默认导入，然后在开头加入了messagebox的导入，程序就可以正常执行了
from tkinter import *
from tkinter import messagebox
def test_show():
messagebox.showinfo(None, 'first')
root = Tk()
one = Label(root, text = 'First')
one.pack()
two = Button(root, text = 'First', command=test_show)
two.pack()
mainloop()