It checks if the verb_phrase object contains an input string that matches a causative suffix, instantiates, when a matching string is found, a causative suffix object in the Suffix class, and registers the suffix object as a component of the verb phrase object, before returning to the system the verb phrase object with the added information.
when it has been found and registered, that means a suffix that may appear before the inflection has also been recorded in the verb phrase instance.