If you're a VIM user and a Python coder, that could interest you.
Syntastic can be used to check for syntax errors in files opened in VIM. It has a pretty extensive list of supported languages.
For Python it had PyFlakes, and since the latest version, it has my small glue script "Flake8", that reunites in a single stream: pep8, PyFlakes and a McCabe checker.
For Flake8 the next step is to support Python 3 -- as soon as I find some time, or a volunteer ;)
Thanks to Sylvain Soliman (and Clayton Parker) !