from Tkinter import *

def greet():
   print "hello world"

win = Frame()
win.pack()

Button(win, text = 'hello', command=greet).pack(side=LEFT,fill=Y)
Label(win, text="Hello world").pack(side=TOP)
Button(win,text='quit',command=win.quit).pack(side=RIGHT,expand=YES,fill=X)

win.mainloop()