Logging on to site to web scrape in Python

I want to scrape data from a website which has an initial log on (where I have working credentials). It is not possible to inspect the code for this, at is a log on that pops up before visiting the site. I tried searching around, but did not find any answer - perhaps I do not know what to search for.

This is what you get when going to the site:

Log on

Any help is appreciated :-)