def get_comment_notification_session(self, comment_receiver=None):
raise Unimplemented()<EOL>
Gets the ``OsidSession`` associated with the comment notification service.

        arg:    comment_receiver (osid.commenting.CommentReceiver): the
                receiver
        return: (osid.commenting.CommentNotificationSession) - a
                ``CommentNotificationSession``
        raise:  NullArgument - ``comment_receiver`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - ``supports_comment_notification()`` is
                ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_comment_notification()`` is ``true``.*