name : subclass-existing-widgets.py from Tkinter import * # This is a program that makes a simple two button application class New_Button(Button): def callback(self): print self.counter self.counter = self.counter + 1 def createWidgets(top): f = Frame(top) f.pack() f.QUIT = Button(f, text='QUIT', foreground='red', command=top.quit) f.QUIT.pack(side=LEFT, fill=BOTH) # a hello button f.hi_there = New_Button(f, text='Hello') # we do this on a different line because we need to reference f.hi_there f.hi_there.config(command=f.hi_there.callback) f.hi_there.pack(side=LEFT) f.hi_there.counter = 43 root = Tk() createWidgets(root) root.mainloop()