$ python -c "import libvirt; print libvirt"
\<module 'libvirt' from '/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/libvirt.pyc'>
$ ls /Library/Python/2.7/site-packages 
README                     vboxapi                    vboxapi-1.0-py2.7.egg-info