Using config files written in Python [closed]

Question

I've noticed a few Python packages that use config files written in Python. Apart from the obvious privilege escalation, what are the pros and cons of this approach?

Is there much of a precedence for this? Are there any guides as to the best way to implement this?

Just to clarify: In my particular use case, this will only be used by programmers or people who know what they're doing. It's not a config file in a piece of software that will be distributed to end users.