Missing instructions on using with both py2 & py3

Goal: work with packages like "bandit" - which may need both py2 & py3 versions installed (since they use the AST module of the python executable).

There are 2 challenges here:

• being able to specify the python to be used during the install (the --python option to virtualenv)
• being able to append the "usual" suffixes for each version (since both bandit2 and bandit3 would be in ~/.local/bin/

I've seen hints on the web that such a setup is possible, however I have not been able to find the details anywhere.