@abc.abstractmethod<EOL><INDENT>def get_grade_entry_notification_session(self, receiver):<DEDENT>
return<EOL>
Gets the notification session for notifications pertaining to grade entry changes.

        :param receiver: the grade entry receiver
        :type receiver: ``osid.grading.GradeEntryReceiver``
        :return: a ``GradeEntryNotificationSession``
        :rtype: ``osid.grading.GradeEntryNotificationSession``
        :raise: ``NullArgument`` -- ``receiver`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``Unimplemented`` -- ``supports_grade_entry_notification()`` is ``false``

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