@abc.abstractmethod<EOL><INDENT>def get_end_reason(self):<DEDENT>
return<EOL>
Gets a state indicating why this relationship has ended.

        :return: a state
        :rtype: ``osid.process.State``
        :raise: ``IllegalState`` -- ``has_end_reason()`` is ``false``
        :raise: ``OperationFailed`` -- unable to complete request

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