apt-get error: cnf-update-db - KeyError: 'suite' (focal)

[jj05]

"apt-get update" fails to run when command-not-found is installed on Ubuntu 20.04.

To reproduce with Docker:
docker pull ubuntu:20.04 # Pull latest Ubuntu 20.04 docker image
docker run -it ubuntu:20.04 # Start an Ubuntu 20.04 docker container

# Within the container run:
apt-get update
apt-get -yy dist-upgrade
apt-get -yy install command-not-found
exec bash # Reload bash to load command-not-found
apt-get update # Update command-not-found database

Traceback (most recent call last):
  File "/usr/lib/cnf-update-db", line 26, in <module>
    col.create(db)
  File "/usr/lib/python3/dist-packages/CommandNotFound/db/creator.py", line 93, in create
    self._fill_commands(con)
  File "/usr/lib/python3/dist-packages/CommandNotFound/db/creator.py", line 127, in _fill_commands
    self._parse_single_commands_file(con, fp)
  File "/usr/lib/python3/dist-packages/CommandNotFound/db/creator.py", line 165, in _parse_single_commands_file
    suite=tagf.section["suite"]
KeyError: 'suite'
Reading package lists... Done
E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db; then /usr/lib/cnf-update-db > /dev/null; fi'
E: Sub-process returned an error code

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.