constructing/deserializing the type parses (and therefore validates) the port list anyway and afaik the verify function doesn't really add anything to the API documentation either (correct me if I am wrong) - so we could skip adding a verification function to the schema entirely?
This is required if you still want to use it a String with VerifyFn. Or if you simply want to check an input text field in the GUI. If you don't do that, you do not need it...
