Using property() to extend Tkinter classes but Tkinter classes are old-style classes?

Robert Kern robert.kern at
Tue Nov 30 19:49:05 CET 2010

On 11/30/10 11:00 AM, Giacomo Boffi wrote:
> Terry Reedy<tjreedy at>  writes:
>> On 11/28/2010 3:47 PM, python at wrote:
>>> I had planned on subclassing Tkinter.Toplevel() using property() to wrap
>>> access to properties like a window's title.
>>> After much head scratching and a peek at the source, I
>>> realized that all Tkinter classes are old-style classes (even under
>>> Python 2.7).
>>> 1. Is there a technical reason why Tkinter classes are still old-style
>>> classes?
>> To not break old code. Being able to break code by upgrading all
>> classes in the stdlib was one of the reasons for 3.x.
> In 3.x, are Tkinter classes still derived by old-style classes?


[~]$ python3
Python 3.1.2 (r312:79360M, Mar 24 2010, 01:33:18)
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
 >>> import tkinter
 >>> tkinter.Tk.mro()
[<class 'tkinter.Tk'>, <class 'tkinter.Misc'>, <class 'tkinter.Wm'>, <class 

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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