@abc.abstractmethod<EOL><INDENT>def set_end_reference_event(self, event_id):<DEDENT>
pass<EOL>
Sets the fixed end time.

        :param event_id: the end reference event ``Id``
        :type event_id: ``osid.id.Id``
        :raise: ``InvalidArgument`` -- ``event_id`` is invalid
        :raise: ``NoAccess`` -- ``event_id`` cannot be modified
        :raise: ``NullArgument`` -- ``event_id`` is ``null``

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