mainloop()

vahid_tkinter.py

#!/usr/sbin/env python
from Tkinter import *
#from ttk import *
import ttk

win=Tk()

def create_frame1():
    global show_frame2, frame1
    frame1=ttk.Frame(win)
    lbl=ttk.Label(frame1, text='Frame1', font='Times 35')
    lbl.grid(row=0, column=0, columnspan=2)
    bt_next=ttk.Button(frame1, text='Next', command=show_frame2)
    bt_quit=ttk.Button(frame1, text='Quit', command=win.destroy)
    bt_next.grid(row=1, column=1)
    bt_quit.grid(row=1, column=0)

def show_frame1():
    global frame2, frame1
    frame2.grid_forget()
    frame1.grid()

def create_frame2():
    global show_frame3, show_frame1, frame2
    frame2=ttk.Frame(win)
    lbl=ttk.Label(frame2, text='Frame2', font='Times 35')
    lbl.grid(row=0, column=0, columnspan=2)
    bt_next=ttk.Button(frame2, text='Next', command=show_frame3)
    bt_next.grid(row=1, column=1)
    bt_back=ttk.Button(frame2, text='Back', command=show_frame1)
    bt_back.grid(row=1, column=0)
    
def show_frame2():
    global farme1, frame3, frame2
    frame3.grid_forget()
    frame1.grid_forget()
    frame2.grid()

def create_frame3():
    global show_frame2, frame3
    frame3=ttk.Frame(win)
    lbl=ttk.Label(frame3, text='Frame3', font='Times 35')
    lbl.grid(row=0, column=0, columnspan=2)
    bt_back=ttk.Button(frame3, text='Back', command=show_frame2)
    bt_back.grid(row=1, column=0)
    bt_quit=ttk.Button(frame3, text='Quit', command=win.destroy)
    bt_quit.grid(row=1, column=1)

def show_frame3():
    global frame2, frame3
    frame2.grid_forget()
    frame3.grid()

def main():
    create_frame1()
    create_frame2()
    create_frame3()
    show_frame1()
    win.mainloop()

if __name__ == "__main__":
    main()