converting base class instance to derived class instance

[François Pinard]

[John Roth]

> > If you want to do a little bit of deep magic, a factory function can
> > create an instance by calling object(), [...] My goof. The correct
> > call is: object.__new__(klas) [...]

OK, thanks. `object.__new__' is what I was using already.  It was
looking kosher to me because of the explanations in `descrintro'.  Maybe
I was seduced and tempted by the announced bit of deep magic, and was
trying to rediscover the secret.  My little Harry Potter side! :-)

-- 
François Pinard   http://www.iro.umontreal.ca/~pinard