The python package was incorrectly named dbus in the requirements.txt. It was renamed to the actual dependency dbus-python in the bullseye branch, but it would be nice to add a test to run the tox -e py39 on the CI, however it requires the dependency of dbus to be installed on the CI as bindep does not seem to resolve it and the build will fail on the CI. Tests like this are minimal but avoid mistakes like these.