def get_root_objective_banks(self):
<EOL>if self._catalog_session is not None:<EOL><INDENT>return self._catalog_session.get_root_catalogs()<EOL><DEDENT>return ObjectiveBankLookupSession(<EOL>self._proxy,<EOL>self._runtime).get_objective_banks_by_ids(list(self.get_root_objective_bank_ids()))<EOL>
Gets the root objective banks in this objective bank hierarchy.

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