Python security

[Dustin Lee]

I'm currently writing a research paper about language based security.
In particular I'm looking at how features of a language encourage the
writing of secure programs and how the the execution environment
enforces particular security policies.  With respect to Python I've been
investigating "rexec" and "Bastion".  I'm curious if there are other
language based security features I should be looking at within Python.
I'm also interested in any papers/articles that talk about Python
security and what design decisions went into it.  I've found some
materials with a simple Google search but I'm curious what resources
practicing Python programmers have found the most useful.

thanks in advance,

dustin