Compatibility with lower versions of Python

[crodriguez1a]

Initially, the lib had planned to make use of data classes (which are only available past Python 3.7). This is no longer the case, and the lib can now be made available to lower versions.

The primary motivation for this update to support compatibility with pre-configured python environments like Google Colab that run on 3.6.x by default.

• Support Python 3.6.x