Python 3.5 users should be able to modify default settings, once you upgrade the package's install of lesscpy
fantastic thanks for heads up!
Still waiting for 3.5 compatibility to make it's way into the official release on pypi. I've opened an issue here asking when to anticipate an updated official release.
Cool, thanks for the update!
As far as I can tell, lesscpy 0.11.1 (via pip) is working with 3.5
Accodring to PyPI, lesscpy is, as of 04.10.16, at version 0.12 and officially supporting Python 3.5 (if I'm reading PyPI page correctly, that is).
Thanks for the updates, just released a new version that should (hopefully) allow full functionality for Python3.5 users. Leaving this issue open for now in case any problems arise.
Can only speak for myself, of course, but, works perfectly on Ubuntu 16.04 with Python 3.5.2.
(Screenshot showing oceans16 theme with FiraCode font).
Thanks for making this plugin, generally, and making it fully functional with Python 3.5+!

Totally, glad it's working!
I'll close this out then.
Most helpful comment
Thanks for the updates, just released a new version that should (hopefully) allow full functionality for Python3.5 users. Leaving this issue open for now in case any problems arise.