Tableau REST API provide a method to get cross-tab data, like CSV, from particular view.
To achieve it, you need
1) sign in to Server.
2) specify site id and view id which you want to get data.
3) get response with Query View Data.
4) fetch (and split) response body.
5) use csv.writer() to convert fetched data to CSV.
Please note that users need Read permission to use this api function.