PSA: Debian Stretch, apt-listchanges, and Python 3

[Chris Angelico]

If, like me, you build Python 3.6 from source and make it your default
'python3' binary, you may run into issues with the latest
apt-listchanges, which has switched to using Python 3. The symptom is
an ImportError trying to "import debconf", which is available in
dist-packages in the system Python, but (naturally) isn't part of
Python 3.6's install tree.

My solution:

sudo ln -s /usr/lib/python3/dist-packages/debconf.py
/usr/local/lib/python3.6/site-packages/

And then apt-listchanges happily sets itself up.

ChrisA