List installed packages not part of Debian 'stable'

apt-list-non-debian-stable-packages.py

#!/usr/bin/env python3

import apt

ORIGINS = frozenset(['stable', 'stable-security'])
CACHE = apt.Cache()

for pkg in filter(lambda p: p.installed, CACHE):
    origins = pkg.versions[pkg.candidate].origins
    if not any(( o for o in origins if o.archive in ORIGINS )):
        print(pkg, origins[0].archive, origins[0].site)