code: def get_child_repository_ids(self, repository_id):
          
          # Implemented from template for
          # osid.resource.BinHierarchySession.get_child_bin_ids
          if self._catalog_session is not None:
              return self._catalog_session.get_child_catalog_ids(catalog_id=repository_id)
          return self._hierarchy_session.get_children(id_=repository_id)
docs: Gets the ``Ids`` of the children of the given repository.
  
          arg:    repository_id (osid.id.Id): the ``Id`` to query
          return: (osid.id.IdList) - the children of the repository
          raise:  NotFound - ``repository_id`` not found
          raise:  NullArgument - ``repository_id`` is ``null``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          *compliance: mandatory -- This method must be implemented.*