python development practices?

[Laura Creighton]

Be careful with the leading underscore thingie.  I have more trouble
with python code written by people (who don't work here) who apparantly
as a last step turn _every_ attribute in their class into a _variable.
I come along and want to subclass them, or make a helper class ....
I'm also tired of finding 3 classes which absolutely, positively,
_must_ live in the same file; especially since this is so rarely documented.

Laura Creighton