import tkinter as tk from tkinter import messagebox as mb  def answer():     mb.showerror("Answer", "Sorry, no answer available")  def callback():     if mb.askyesno('Verify', 'Really quit?'):         mb.showwarning('Yes', 'Not yet implemented')     else:         mb.showinfo('No', 'Quit has been cancelled')  tk.Button(text='Quit', command=callback).pack(fill=tk.X) tk.Button(text='Answer', command=answer).pack(fill=tk.X) tk.mainloop() 

Read more of this post