BANK ACCOUNT SECURITY GRANT Using rest API CALL?

Summary:

Oracle provides a rest API for creating Bank account grant but not able to use it. Please provide sample code or guide what is wrong in below code. Documentation:

Business requirement to update hundreds of bank accounts and 10 user ids to bank account security. That is why exploring this rest API route. Otherwise, this is labor intensive manual UI activity of whole day or more depending on no of rows to be updated.

Content (required):

As per above document, it is expecting Grant Id but not sure how this can be provided because REST API should create a new grant and it is a database sequence, should not be part of rest API call ideally.