I needed to install python 2.7 in my Debian system, and did
apt-get install python2.7. However, the package version is 2.7.3rc2, while the stable 2.7.3 is already available at http://python.org. I used the python from the Debian repository for a while and installed a couple of packages (like numpy) before trying to upgrade.
Then, I downloaded the 2.7.3 source, compiled and installed it (following the idea from this script: https://gist.github.com/2659457), and it became a huge mess: The additional modules I installed for python 2.7.3rc2 are not accessible for python 2.7. And I just don't know how I can delete them and clear things out.