@abc.abstractmethod<EOL><INDENT>def get_assessment_results_session(self):<DEDENT>
return<EOL>
Gets an ``AssessmentResultsSession`` to retrieve assessment results.

        :return: an assessment results session for this service
        :rtype: ``osid.assessment.AssessmentResultsSession``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``Unimplemented`` -- ``supports_assessment_results()`` is ``false``

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