I'm am working on an bot. I need to app to cart games from code. I found this documentation from steam but I don't really understand it. https://partner.steamgames.com/doc/features/inventory/webfunctions
If this can be used to add a game to cart by appid, please give me an example so I will understand easier
From the steam api you posted, no you cannot add games to cart with python. That api allows you to list items to be purchased and then redirect the user to steam with those items in their checkout. This is all done on the frontend of a webapp using html/js. And since the api requires the user to be redirected to steam to finalize the purchase you cannot do this purely in python.
The only time python is need is in the backend to handle authentication.