import tkinter as tk

LARGE_FONT = ("Verdana", 12)

class SeaofBTCapp(tk.Tk): # put inheritance from other class

def __init__(self, *args, **kwargs): # args: variable; kwargs: dictionary

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 = {}

for F in (StartPage, PageOne, PageTwo):

frame = F(container, self)

self.frames[F] = frame

frame.grid(row=0, column=0, sticky='nsew') # sticky: alignment

self.show_frame(StartPage)

def show_frame(self, cont):

frame = self.frames[cont]

frame.tkraise()

class StartPage(tk.Frame):

def __init__(self, parent, controller):

tk.Frame.__init__(self, parent)

label = tk.Label(self, text="Start Page", font=LARGE_FONT)

label.pack(pady=10, padx=10)

button = tk.Button(self, text='Visit Page 1',

command=lambda: controller.show_frame(PageOne))

button.pack()

button2 = tk.Button(self, text='Visit Page 2',

command=lambda: controller.show_frame(PageTwo))

button2.pack()

class PageOne(tk.Frame):

def __init__(self, parent, controller):

tk.Frame.__init__(self, parent)

label = tk.Label(self, text="Page One", font=LARGE_FONT)

label.pack(pady=10, padx=10)

button1 = tk.Button(self, text='Back to home',

command=lambda: controller.show_frame(StartPage))

button1.pack()

button2 = tk.Button(self, text='Page Two',

command=lambda: controller.show_frame(PageTwo))

button2.pack()

class PageTwo(tk.Frame):

def __init__(self, parent, controller):

tk.Frame.__init__(self, parent)

label = tk.Label(self, text="Page Two", font=LARGE_FONT)

label.pack(pady=10, padx=10)

button1 = tk.Button(self, text='Back to home',

command=lambda: controller.show_frame(StartPage))

button1.pack()

button2 = tk.Button(self, text='Page One',

command=lambda: controller.show_frame(PageOne))

button2.pack()

app = SeaofBTCapp()

app.mainloop()