Python is installed in a local directory.
My directory tree looks like this:
(local directory)/site-packages/toolkit/interface.py
Linux: Imported modules are located in /usr/local/lib/python2.7/dist-packages
If you're using a module compiled in C, don't forget to chmod the .so file after sudo setup.py install.
sudo setup.py install
sudo chmod 755 /usr/local/lib/python2.7/dist-packages/*.so