@abc.abstractmethod<EOL><INDENT>def get_grade_system_search_order(self):<DEDENT>
return<EOL>
Gets the search order for a gradebook column summary search order.

        :return: the gradebook column summary search order
        :rtype: ``osid.grading.GradebookColumnSummarySearchOrder``
        :raise: ``Unimplemented`` -- ``supports_gradebook_column_summary_search_order()`` is ``false``

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