help output displays variable name, rather than its value

[GeekSmith]

Note '$distro-proposed' in the description of the '-p, --proposed' option.

~/ do-release-upgrade --help
Usage: do-release-upgrade [options]

Options:
  -h, --help show this help message and exit
  -V, --version Show version and exit
  -d, --devel-release If using the latest supported release, upgrade to the
                        development release
  --data-dir=DATA_DIR Directory that contains the data files
  -p, --proposed Try upgrading to the latest release using the upgrader
                        from $distro-proposed
  -m MODE, --mode=MODE Run in a special upgrade mode. Currently 'desktop' for
                        regular upgrades of a desktop system and 'server' for
                        server systems are supported.
  -f FRONTEND, --frontend=FRONTEND
                        Run the specified frontend
  -c, --check-dist-upgrade-only
                        Check only if a new distribution release is available
                        and report the result via the exit code
  --allow-third-party Try the upgrade with third party mirrors and
                        repositories enabled instead of commenting them out.
  -q, --quiet
  -e ENV, --env=ENV A comma-separated list of environment variables (e.g.
                        VAR1=VALUE1,VAR2=VALUE2) that should be set during the
                        upgrade.

The man page correctly shows the value of '$distro':
       -p, --proposed
              Try upgrading to the latest release using the upgrader from Ubuntu-proposed

[GeekSmith (lixo-geeksmith)]

This line was added in bzr revision #805, from what I can tell. I don't see $distro defined anywhere in the file. Maybe it used to be defined in an imported file, or maybe this is just broken. This change was made in 2008 and python has changed a bit since then.