def get_root_objectives(self):
url_path = construct_url('<STR_LIT>',<EOL>bank_id=self._catalog_idstr)<EOL>return objects.ObjectiveList(self._get_request(url_path))<EOL>
Gets the root objective in this objective hierarchy.

        return: (osid.learning.ObjectiveList) - the root objective
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        compliance: mandatory - This method is must be implemented.