# from Practical Python, by Magnus Lie Hetland

from Tkinter import *
def hello(): print 'Hello, world!'
win = Tk() # Tkinter's 'main window'
win.title('Hello, Tkinter!')
win.geometry('200x100') # Size 200, 200

btn = Button(win, text='Hello', command=hello)
btn.pack(expand=YES, fill=BOTH)

mainloop()