Because the python dbus module is not supported any longer and libnotify does blocking I/O, In Pithos we have recently removed our dbus module and libotify bindings dependency in favor of our own implementations. Both should work for your purposes and be drastic improvements over what they replace. They do require Python 3. I'm not sure if that is a deal breaker. Your project doesn't say which if any version of Python is explicitly supports.
Because the python dbus module is not supported any longer and libnotify does blocking I/O, In Pithos we have recently removed our dbus module and libotify bindings dependency in favor of our own implementations. Both should work for your purposes and be drastic improvements over what they replace. They do require Python 3. I'm not sure if that is a deal breaker. Your project doesn't say which if any version of Python is explicitly supports.
https://github.com/JasonLG1979/possibly-useful-scraps/wiki/GioNotify
https://github.com/pithos/pithos/tree/master/pithos/plugins/dbus_util
https://github.com/pithos/pithos/blob/master/pithos/plugins/_mpris.py
https://github.com/pithos/pithos/blob/master/pithos/plugins/notify.py