notebook.py

try:
    # for Python2
    from Tkinter import *   ## notice capitalized T in Tkinter 
except ImportError:
    # for Python3
    from tkinter import *   ## notice lowercase 't' in tkinter here

class notebook(object): 
	def __init__(self, master, side=LEFT): 
		self.active_fr = None 
		self.count = 0 
		self.choice = IntVar() ## was (0) 
		if side in (TOP, BOTTOM): 
			self.side = LEFT 
		else: self.side = TOP 
		self.rb_fr = Frame(master, borderwidth=2, relief=GROOVE) 
		self.rb_fr.pack(side=side, fill=BOTH) 
		self.screen_fr = Frame(master, borderwidth=2, relief=FLAT) 
		self.screen_fr.pack(fill=BOTH) 

	def __call__(self): 
		return self.screen_fr 

	def add_screen(self, fr, title): 
		b = Radiobutton(self.rb_fr, text=title, indicatoron=0, variable=self.choice, value=self.count, command=lambda: self.display(fr)) 
		b.pack(fill=BOTH, side=self.side) 
		if not self.active_fr: 
			fr.pack(fill=BOTH, expand=1) 
		self.active_fr = fr 
		self.count += 1 

	def display(self, fr): 
		self.active_fr.forget( ) 
		fr.pack(fill=BOTH, expand=1) 
		self.active_fr = fr