@abc.abstractmethod<EOL><INDENT>def get_assessment_ids(self):<DEDENT>
return<EOL>
Gets the ``Ids`` of any assessments associated with this activity.

        :return: list of assessment ``Ids``
        :rtype: ``osid.id.IdList``
        :raise: ``IllegalState`` -- ``is_assessment_based_activity()`` is ``false``

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