As I commented on the commit c0bf88e, c0bf88ea05
python3-validity.service does not start, at least on Debian buster, since
safe_load() does not have arg Loader on its prototype.
Removing Loader here,
config = yaml.safe_load(configfd)
makes it back to normal starting.
```
Aug 02 20:42:54 t480 dbus-service[60937]: Traceback (most recent call last):
Aug 02 20:42:54 t480 dbus-service[60937]: File "/usr/lib/python-validity/dbus-service", line 307, in <module>
Aug 02 20:42:54 t480 dbus-service[60937]: main()
Aug 02 20:42:54 t480 dbus-service[60937]: File "/usr/lib/python-validity/dbus-service", line 245, in main
Aug 02 20:42:54 t480 dbus-service[60937]: config = yaml.load(configfd)
Aug 02 20:42:54 t480 dbus-service[60937]: File "/usr/lib/python3.9/site-packages/yaml/__init__.py", line 109, in load
Aug 02 20:42:54 t480 dbus-service[60937]: raise RuntimeError("Unsafe load() call disabled by Gentoo. See bug #659348")
Aug 02 20:42:54 t480 dbus-service[60937]: RuntimeError: Unsafe load() call disabled by Gentoo. See bug #659348
```
Relevant Gentoo bug report https://bugs.gentoo.org/659348
Replacing yaml.load() calls with yaml.safe_load() should fix it