@abc.abstractmethod<EOL><INDENT>def get_value_notification_session(self, value_receiver):<DEDENT>
return<EOL>
Gets a value notification session.

        :param value_receiver: the notification callback
        :type value_receiver: ``osid.configuration.ValueReceiver``
        :return: a ``ValueNotificationSession``
        :rtype: ``osid.configuration.ValueNotificationSession``
        :raise: ``NullArgument`` -- ``value_receiver`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``Unimplemented`` -- ``supports_value_notification()`` is ``false``

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