FYI, if you want to use a Fedora 28 hypervisor with virt-who, it’s broken at the moment. First, the version published with F28 updates repo is quite old, 0.17. You can get a more recent version, 0.22, from the updates-testing repo, but it’s also broken.
If you use the old 0.17 version, here’s the workaround:
pip install -U git+https://github.com/candlepin/python-rhsm#egg=rhsm
If you used the updates-testing Fedora repo (sudo dnf update virt-who --enablerepo updates-testing
):
sudo pip3 install -U libvirt-python
The Candlepin team is already aware of both issues.