@abc.abstractmethod<EOL><INDENT>def get_relationships_by_search(self, relationship_query, relationship_search):<DEDENT>
return<EOL>
Gets the search results matching the given search query using the given search.

        :param relationship_query: the relationship query
        :type relationship_query: ``osid.relationship.RelationshipQuery``
        :param relationship_search: the relationship search
        :type relationship_search: ``osid.relationship.RelationshipSearch``
        :return: the returned search results
        :rtype: ``osid.relationship.RelationshipSearchResults``
        :raise: ``NullArgument`` -- ``relationship_query`` or ``relationship_search`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure
        :raise: ``Unsupported`` -- ``relationship_query`` or ``relationship_search`` is not of this service

        *compliance: mandatory -- This method must be implemented.*