@abc.abstractmethod<EOL><INDENT>def get_relationships_by_genus_type_for_peers(self, source_id, destination_id, relationship_genus_type):<DEDENT>
return<EOL>
Gets a ``RelationshipList`` corresponding between the given peer ``Ids`` and relationship genus ``Type.

        Relationships`` of any genus derived from the given genus are
        returned.

        In plenary mode, the returned list contains all of the
        relationships corresponding to the given peer or an error
        results if a relationship is inaccessible. Otherwise,
        inaccessible ``Relationships`` may be omitted from the list.

        In effective mode, relationships are returned that are currently
        effective. In any effective mode, effective relationships and
        those currently expired are returned.

        :param source_id: a peer ``Id``
        :type source_id: ``osid.id.Id``
        :param destination_id: a related peer ``Id``
        :type destination_id: ``osid.id.Id``
        :param relationship_genus_type: a relationship genus type
        :type relationship_genus_type: ``osid.type.Type``
        :return: the relationships
        :rtype: ``osid.relationship.RelationshipList``
        :raise: ``NullArgument`` -- ``source_id, destination_id,`` or ``relationship_genus_type`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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