polib is a library to manipulate, create, modify gettext files (pot, po and mo
files). You can load existing files, iterate through its entries, add, modify
entries, comments or metadata, etc. or create new po files from scratch.

polib supports out of the box any version of python ranging from 2.4 to latest
3.X version.

polib is pretty stable now and is used by many opensource projects.

polib is completely free and opensource, the license used is the MIT license.
It was developed back in 2006 by David Jean Louis and it is still actively
maintained.