Python 2.7 Tkinter Code -

my tkinter code showing no problems when run nothing shows up. wrong?

i'm using python 2.7. it's supposed pizzeria game way

here code:

import tkinter tk tkinter import stringvar import ttk random import randint , choice ,uniform  class window(tk.tk):     def __init__(self, *args, **kwargs):         tk.tk.__init__(self, *args, **kwargs)         container = tk.frame(self)         container.pack(side="top", fill="both", expand = true)         container.grid_rowconfigure(0, weight=1)         container.grid_columnconfigure(0, weight=1)         self.frames = {}         f in (startpage, easy, hard):             frame = f(container, self)             self.frames[f] = frame             frame.grid(row=0, column=0, sticky="nsew")         self.show_frame(startpage)      def show_frame(self, cont):         frame = self.frames[cont]         frame.tkraise()   class startpage():     tk.label(text = "welcome!" , font = ("verdana", 12)).pack()     ttk.button(text = "play" , command = lambda: window().show_frame(play()))  class play():     def loop():         q = randint(0, 10)         p = uniform(1.50 , 10.50)         t = uniform(.1, .9)         p2 = p*q         p3 = p2*t         g = stringvar()         ttk.entry(textvariable=g).pack()         ttk.label(text = "price per pizza: " + str(p) + " amount: " + str(q) + " tax: " + str(t))         if g == p3 : ttk.label(text = "correct!")         elif g != p3: ttk.label(text = "try again.")     loop()     ttk.button(text = "play" , command = lambda: loop())  window.mainloop 

this nothing, since reference mainloop method of window class

window.mainloop 

you need create instance of window class before call mainloop

w = window() w.mainloop()