code: def get_root_gradebook_ids(self):
          
          # Implemented from template for
          # osid.resource.BinHierarchySession.get_root_bin_ids
          if self._catalog_session is not None:
              return self._catalog_session.get_root_catalog_ids()
          return self._hierarchy_session.get_roots()
docs: Gets the root gradebook ``Ids`` in this hierarchy.
  
          return: (osid.id.IdList) - the root gradebook ``Ids``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          *compliance: mandatory -- This method must be implemented.*