To contribute, just fork the repo, make changes, and finally issue a pull-request. As a general rule, consistency trumps most of the other non-functional requirements :)
We (try to) follow the PEP8 conventions, i.e. snake_case for variables and functions and PascalCase for Classes.
Tests should be written in the Unittest-Framework and we encourage the use of TDD (in a reasonable, non-religious way, make sure you have watched the great talk https://www.youtube.com/watch?v=EZ05e7EMOLM).