@abc.abstractmethod<EOL><INDENT>def get_rubric(self):<DEDENT>
return<EOL>
Gets the rubric.

        :return: the assessment taken
        :rtype: ``osid.assessment.AssessmentTaken``
        :raise: ``IllegalState`` -- ``has_rubric()`` is ``false``
        :raise: ``OperationFailed`` -- unable to complete request

        *compliance: mandatory -- This method must be implemented.*