if (is_array($keys)) {
                $sql_keys = " WHERE `key` IN ('".implode("','", $keys)."')";
            } elseif (is_string($keys)) {
                $sql_keys = $this->db instanceof sql_db ? " WHERE `key` = '".$this->db->real_escape_string($keys)."'" : " WHERE `key` = " . $keys; 
            } else {