@abc.abstractmethod<EOL><INDENT>def get_assessments_completed(self):<DEDENT>
return<EOL>
Gets all the assessments completed by this agent.

        :return: the completed assessments
        :rtype: ``osid.assessment.AssessmentTakenList``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure occurred

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