Needed: Real-world examples for Python's Cooperative Multiple Inheritance

Antoine Pitrou solipsis at
Thu Nov 25 00:46:51 CET 2010

On Wed, 24 Nov 2010 12:08:04 -0800 (PST)
Raymond Hettinger <python at> wrote:
> I'm writing-up more guidance on how to use super() and would like to
> point at some real-world Python examples of cooperative multiple
> inheritance.
> Google searches take me to old papers for C++ and Eiffel, but that
> don't seem to be relevant to most Python programmers (i.e. a
> WalkingMenu example where a submenu is both a Entry in a Menu and a
> Menu itself).  Another published example is in a graphic library where
> some widgets inherit GraphicalFeature methods such as location, size
> and NestingGroupingFeatures such as finding parents, siblings, and
> children.  I don't find either of those examples compelling because
> there is no particular reason that they would have to have overlapping
> method names.
> So far, the only situation I can find where method names necessarily
> overlap is for the basics like __init__(), close(), flush(), and
> save() where multiple parents need to have their own initialization
> and finalization.
> If you guys know of good examples, I would appreciate a link or a
> recap.

I have never seen a good use of cooperative multiple inheritance in
Python. My own experience trying to use it suggests me that I would
have been better with independent "handler" classes (urllib2-style).



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