Python issues in extractions.py

[skdebray]

The are a couple of minor Python issues in file extractions.py in the branch design-attempt-01 that should be fixed before we merge everything into main:

• I'd like to try and stay with the style guidelines in PEP-8 (https://peps.python.org/pep-0008/). One of the guidelines is that lines of code are at most 79 characters long. This file has a few lines longer than that, these need to be fixed. This tool may be helpful for this: https://github.com/astral-sh/ruff
• It would be helpful to have some documentation at the top indicating the purpose of this code and also how it should be invoked.
• For each of the classes defined in this file, some documentation indicating what it's for and where+how it will be used.

Thanks!