from threading import Timer
from tkinter import *
import tkinter.messagebox

def show(message):
    tkinter.messagebox.showinfo("Test", message)

class Application(Frame):
    def say_hi(self):
        print("saying hi")
        show("hi there, everyone!")

    def hang(self):
        print("will hang now with show()")
        show("hang")
    
    def starthang(self):
        print("hanging in 2")
        Timer(2, self.hang, ()).start()
    
    def createWidgets(self):
        self.QUIT = Button(self)
        self.QUIT["text"] = "QUIT"
        self.QUIT["fg"] = "red"
        self.QUIT["command"] = self.quit

        self.QUIT.pack({"side": "left"})

        self.hi_there = Button(self)
        self.hi_there["text"] = "Hello",
        self.hi_there["command"] = self.say_hi

        self.hi_there.pack({"side": "left"})

        self.hi_there = Button(self)
        self.hi_there["text"] = "Hang",
        self.hi_there["command"] = self.starthang
        
        self.hi_there.pack({"side": "left"})
        
    def __init__(self, master=None):
        Frame.__init__(self, master)
        self.pack()
        self.createWidgets()

root = Tk()
app = Application(master=root)
app.mainloop()
root.destroy()