Sorry for the fat finger and earlier incomplete message...
Although RHEL 7/CentOS 7 don't come with python3 in the base OS, it would be nice to have app_python3.so packaged for more extensive exposure in the wild.
Can I suggest that kamailio OBS be built against the python3 packages in Software Collections? Currently rh-python36 is on RHEL and Software Collections for CentOS.
Cheers
Anthony Alba