It unfollows users you're following, it runs in the background so you can still do what you do without it bothering you.
It's not really fast it takes 3 seconds per unfollow if you're following a lot of people it will take awhile.
It's only used on Chrome so make sure you change the (PATH = "C:\Program Files (x86)\chromedriver.exe") where your chromedriver.exe is.
Selenium document : https://selenium-python.readthedocs.io/index.html

This is the chrome driver you need to download to put in your C:\Program Files (x86)

https://sites.google.com/a/chromium.org/chromedriver/downloads

pip install selenium