code: def get_grade_ids(self):
          
          # Implemented from template for osid.repository.Asset.get_asset_content_ids_template
          id_list = []
          for grade in self.get_grades():
              id_list.append(grade.get_id())
          return IdList(id_list)
docs: Gets the grade ``Ids`` in this system ranked from highest to lowest.
  
          return: (osid.id.IdList) - the list of grades ``Ids``
          raise:  IllegalState - ``is_based_on_grades()`` is ``false``
          *compliance: mandatory -- This method must be implemented.*