Append new custom type with API instead of replacing everything

[florian-guily]

Hey, i want to use the Metadata API to add custom types to use them in actions. The problem is that they will be added by users from a form like interface. I was thinking about using the "set_custom_actions" function but this "override" the list of custom actions with the body of the request. Is there a way to "append" the new custom actions to the list of already existing ones instead of replacing everything ?