Since this repo mostly contains notebooks, you should consider adding a tool that enables notebook reviews. e.g. PR #3 can be reviewed at gitnotebooks.com/blobcity/python-for-data-science/pull/3

The UI for PR #3 looks like this, with the ability to add comments:

Full disclosure, I'm the developer, trying to spread the word. If you think this tool can help you out, you can install it from the website, and if this feels spammy, my apologies, you can go ahead and close out the issue.