@abc.abstractmethod<EOL><INDENT>def get_calendar_notification_session(self, calendar_receiver):<DEDENT>
return<EOL>
Gets the notification session for notifications pertaining to calendar service changes.

        :param calendar_receiver: the calendar receiver
        :type calendar_receiver: ``osid.calendaring.CalendarReceiver``
        :return: a ``CalendarNotificationSession``
        :rtype: ``osid.calendaring.CalendarNotificationSession``
        :raise: ``NullArgument`` -- ``calendar_receiver`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``Unimplemented`` -- ``supports_calendar_notification() is false``

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