@abc.abstractmethod<EOL><INDENT>def get_offset_event_notification_session(self, offset_event_receiver):<DEDENT>
return<EOL>
Gets the notification session for notifications pertaining to offset event changes.

        :param offset_event_receiver: the offset event receiver
        :type offset_event_receiver: ``osid.calendaring.OffsetEventReceiver``
        :return: an ``OffsetEventNotificationSession``
        :rtype: ``osid.calendaring.OffsetEventNotificationSession``
        :raise: ``NullArgument`` -- ``offset_event_receiver`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``Unimplemented`` -- ``supports_offset_event_notification()`` is ``false``

        *compliance: optional -- This method must be implemented if
        ``supports_offset_event_notification()`` is ``true``.*