I am a big fan of the syntastic package. In python, it is useful for viewing both Pyflakes and Bandit errors. However, this only works if syntastic knows what python interpreter to use. Not everyone is fortunate enough to have upgraded all of their software to python3. For reasons out of my control, I end up spending most of my time writing python2 code. This means that the times when I finally get to write python3, all of my syntax checking is broken. How cool would it be to have VIM determine what version of python to use automatically? So, begins my grand experiment...
For this to work, I will be using a virtualenv for python2 and one for python3. It's not absolutely necessary to use virtualenvs but I definitely recommend it. Setting up virtualenvs is out of the scope of this gist but make sure that each virtualenv