public function setResult(&$result) {
        if (!is_null($result) &&
            !$result instanceof Garp_Db_Table_Row &&
            !$result instanceof Garp_Db_Table_Rowset) {
                throw new InvalidArgumentException(__METHOD__.' expects parameter 1 to be a'.
                    'Garp_Db_Table_Row or Garp_Db_Table_Rowset. '.gettype($result).' given.');
        }
        $this->_result = $result;
    }