docs: def has_child_vaults(self, vault_id):
          """Tests if a vault has any children.
  
          arg:    vault_id (osid.id.Id): a ``vault_id``
          return: (boolean) - ``true`` if the ``vault_id`` has children,
                  ``false`` otherwise
          raise:  NotFound - ``vault_id`` is not found
          raise:  NullArgument - ``vault_id`` is ``null``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          *compliance: mandatory -- This method must be implemented.*
  
          """
          # Implemented from template for
          # osid.resource.BinHierarchySession.has_child_bins
          if self._catalog_session is not None:
              return self._catalog_session.has_child_catalogs(catalog_id=vault_id)
          return self._hierarchy_session.has_children(id_=vault_id)