I've packaged a vim plugin that provides live code checking for Python 2 and 3 using pyflakes. Combined with code completion from vim-youcompleteme it makes vim feel very IDE-like. I often find it pointing out mistakes in my Python without needing to run the code. vim-khuno is available in testing and unstable.
https://tracker.debian.org/pkg/vim-khuno Screencast and documentation available here: https://github.com/alfredodeza/khuno.vim I thought this will be of interest to any vim user writing Python. -- Edward.