@abc.abstractmethod<EOL><INDENT>def get_assessments(self):<DEDENT>
return<EOL>
Gets all ``Assessments``.

        In plenary mode, the returned list contains all known
        assessments or an error results. Otherwise, the returned list
        may contain only those assessments that are accessible through
        this session.

        :return: a list of ``Assessments``
        :rtype: ``osid.assessment.AssessmentList``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure occurred

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