Confirm Python 3 support

[impredicative]

I understand that this repo was developed in a short amount of time, but Python 2.7 should never be used for any new project. It is unreasonable to require it, given that it is just a year away from expiration. Refer to https://pythonclock.org/ .

Please confirm the code works under the current version of Python, i.e. 3.x.