Suppose you'd already published a Triangle class API and then discovered you needed more dynamism. The property feature lets you sneak in some methods without changing the already-published API and breaking client code.

A lot of these lessons about robust software development come from group or community efforts. Some aspects of Python maybe don't much excite you because you're primarily a solo coder (as am I much of the time).

Not claiming this is directly counter to the above, but it is interesting in this context to look at something happening on the ground, re: Django "Model syntax changed" http://www.djangoproject.com/weblog/2005/aug/25/modelsyntax/ """ This is the first really big community-driven improvement to Django, and it's been awesome to see it come to fruition. Thanks, guys! """ Art