[MM3-users] Migration of archives mailman2 to mailman3: python: can't open file '/opt/mailman/manage.py': [Errno 2] No such file or directory

Your current *) documentation says

Migrate the list archives from Mailman 2 to Mailman 3 by running the following command:
$ python manage.py hyperkitty_import -l foo-list@example.com $var_prefix/archives/private/foo-list.mbox/foo-list.mbox

(venv) /opt/mailman $ python manage.py python: can't open file '/opt/mailman/manage.py': [Errno 2] No such file or directory

What did I wrong or what is that part of your documentation missing?

*) https://docs.mailman3.org/en/latest/migration.html