Installing a user-defined python module in your own system

To make a user-defined python module that you can import in many scripts, you must place your module in one of the site-packages directories in sys.path. If you are not using a virtual environment to run your programs in, then the correct place for this is ~/.local/lib/python3.4/site-packages/. It was meant for exactly this purpose; see PEP 370. If you are using a virtualenv, then you could simply create a symbolic link in the virtualenv site-packages directory to your module. Or you could install your module in /usr/lib/python3.4 with sudo privileges (probably not a good idea though). There should be a way to get virtualenv to look in ~/.local as well, but I have not yet figured this out.