Comment 28 for bug 1768379

I also performed an upgrade of an Ubuntu 16.04 lxc container to artful w/ -proposed enabled without issue.

ubuntu@artful-upgrade:~$ grep -C10 python3-minimal /var/log/dist-upgrade/apt-term.log
Unpacking python3-cryptography (1.9-1) over (1.2.3-1ubuntu0.1) ...
Processing triggers for systemd (234-2ubuntu12.4) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for libc-bin (2.26-0ubuntu2.1) ...
Setting up libssl1.0.0:amd64 (1.0.2g-1ubuntu13.6) ...
Setting up libpython3.6-minimal:amd64 (3.6.3-1ubuntu1) ...
Setting up libexpat1:amd64 (2.2.3-1) ...
Setting up python3.6-minimal (3.6.3-1ubuntu1) ...
Processing triggers for libc-bin (2.26-0ubuntu2.1) ...
(Reading database ... 26272 files and directories currently installed.)
Preparing to unpack .../python3-minimal_3.6.3-0ubuntu3_amd64.deb ...
Unpacking python3-minimal (3.6.3-0ubuntu3) over (3.5.1-3) ...
Setting up python3-minimal (3.6.3-0ubuntu3) ...
(Reading database ... 26272 files and directories currently installed.)
Preparing to unpack .../python3_3.6.3-0ubuntu3_amd64.deb ...
running python pre-rtupdate hooks for python3.6...
Unpacking python3 (3.6.3-0ubuntu3) over (3.5.1-3) ...
Preparing to unpack .../install-info_6.4.90.dfsg.1-1build1_amd64.deb ...
Unpacking install-info (6.4.90.dfsg.1-1build1) over (6.1.0.dfsg.1-5) ...
Setting up install-info (6.4.90.dfsg.1-1build1) ...
(Reading database ... 26272 files and directories currently installed.)
Preparing to unpack .../readline-common_7.0-0ubuntu2_all.deb ...
Unpacking readline-common (7.0-0ubuntu2) over (6.3-8ubuntu2) ...