global variables

[TheFlyingDutchman]

Does anyone know how the variables label and scale are recognized
without a global statement or parameter, in the function resize() in
this code:



#!/usr/bin/env python

from Tkinter import *

def resize(ev=None):
      label.config(font='Helvetica -%d bold' % \
          scale.get())


top = Tk()
top.geometry('250x150')

label = Label(top, text='Hello World!',
    font='Helvetica -12 bold')
label.pack(fill=Y, expand=1)

scale = Scale(top, from_=10, to=40,
     orient=HORIZONTAL, command=resize)
scale.set(12)
scale.pack(fill=X, expand=1)

quit = Button(top, text='QUIT',
    command=top.quit, activeforeground='white',
    activebackground='red')
quit.pack()

mainloop()