apt-cache policy python3
python3:
  Installed: 3.4.0-0ubuntu2
  Candidate: 3.5.1-3
  Version table:
     3.5.1-3 0
        500 http://mirrors.service.networklayer.com/ubuntu/ xenial/main amd64 Packages
 *** 3.4.0-0ubuntu2 0
        100 /var/lib/dpkg/status