Upgrading Class Instances Automatically on Reload

[malv]

Indeed, as I indicated the old recipe/160164 by Michael Hudson works
flawlessly for me.

I am referring here to the latest edition: cookbook #2 which features
an upgraded version.
You find the examples in:
http://examples.oreilly.com/pythoncook2/cb2_examples.zip

The files are named cb2_6_21_*.py, but the book has the recipe in
chapter
20.15. 

malv