ubuntu@juju-lytrusty-machine-7:~$ apt-cache policy python-siz
N: Unable to locate package python-siz
ubuntu@juju-lytrusty-machine-7:~$ apt-cache policy python-six
python-six:
  Installed: 1.5.2-1~ctools0
  Candidate: 1.5.2-1~ctools0
  Version table:
 *** 1.5.2-1~ctools0 0
        400 http://ubuntu-cloud.archive.canonical.com/ubuntu/ precise-updates/cloud-tools/main amd64 Packages
        100 /var/lib/dpkg/status
     1.1.0-2 0
        500 http://nova.clouds.archive.ubuntu.com/ubuntu/ precise/universe amd64 Packages