Not user friendly but does the job.
Fill in params.json and run sh asvz.sh.
You might need to install jq (brew install jq).
id: 6-digit id of the class you want to sign up for. You can find it in the url of the class page.time: when you want your signup request to be sent, specified using the format "YYYY-MM-DD hh:mm:ss".token: you know what this is.
Shoutout to Milos for helping.