Python 2.7 is the minimum dep for the required python-libvirt package

Minimum (python-)libvirt requirement is 0.9.7

Only way to get that is via Ubuntu Precise or newer and requires Python 2.7
http://packages.ubuntu.com/precise-updates/python-libvirt

Lucid has older libvirt / python
http://packages.ubuntu.com/lucid-updates/python-libvirt

However both Debian Squeeze Backport and Wheezy have it available on 2.6
http://packages.debian.org/wheezy/python-libvirt
http://packages.debian.org/squeeze-backports/python-libvirt