def get_objective_hierarchy(self):
<EOL>return ObjectiveBankLookupSession().get_objective_bank(self._objective_bank_id)<EOL>
Gets the hierarchy associated with this session.

        return: (osid.hierarchy.Hierarchy) - the hierarchy associated
                with this session
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        compliance: mandatory - This method must be implemented.