Open Sound Control (OSC) is a protocol for communication among computers, sound synthesizers, and other multimedia devices that is optimized for modern networking technology
I've been using pyOSC for years... and "I was there" when it migrated from Python 2 to 3. Well... if I don't remember well, I asked the maintainer in that moment (Artem Baguinski) to do it!
Now, there're two pages that host pyOSC... and, regarding to your question, one of the pages (the oldest) host Python2 version. And the one in Github (that it is old, too, and not developed any more), the Python3 version.
I'm not sure of pyOSC versions, because OSC.py changelog says nothing about Python version. Maybe it was not correctly docummented.
pyOSC 0.3.5 (Python2): https://trac.v2.nl/wiki/pyOSC
pyOSC 0.3.6 (Python3): https://github.com/ptone/pyosc
As ptr said, it's very easy to implement. I use to connect Blender Game Engine with PureData.