Instances behaviour

[Mr.Rech]

I see your point. Looking again at my metaclass implementation and
comparing it with your abstract class + inheritance approach it turns
out that the latter is definetively more straightforward, easier to
maintain and all in all more pythonic.

Sorry, but being an OOP newbie put me in the position of
overcomplexifing(tm) things a little bit. I'll be back soon with other
(I hope less silly) questions. ;-p

Thanks for all your suggestions,
 Andrea