Oracle Sitehub - How to add Site purpose 'CONTRACTUAL_ATTRIBUTE' for a site from backend/API?

Hello

Generally when someone creates a new store in site hub then he/she can create and include 'CONTRACTUAL_ATTRIBUTE' - site purpose against a store from front end. Now, if want to do the same thing from backend (from database using PL-SQL program) is there any API exists which can do the same task? Because when we will create multiple stores at a time it will be very much time taking process to add site purpose for stores one by one from front end hence seeking help.