Add Python resources

[rafaelcharris]

There are two books with modules and functions to do DiD in python:

• https://mixtape.scunning.com/09-difference_in_differences#bacon-decomposition-theorem
• https://theeffectbook.net/ch-DifferenceinDifference.html?panelset=python-code

I will organize the information and added when I have more time. If anyone finds more information they are welcome to contribute

[grantmcdermott]

I haven't had time to add anything on the Python side—and there are a bunch of R package pages that I still need to write up—but I wanted to flag the following by @bernardodionisi: https://differences.readthedocs.io/en/latest/

[s3alfisc]

To add to this list - I have implemented Gardner's did2s estimator for pyfixest: link =)