static public function formatVariableToPci(ResponseVariable $var) {
        $value = $var->getValue();
        switch($var->getCardinality()){
            case 'single':
                if(strlen($value) === 0){
                    $formatted = ['base' => null];
                }else{
                    try {
                        $formatted = ['base' => [$var->getBaseType() => self::formatStringValue($var->getBaseType(), $value)]];
                    } catch (\common_exception_NotImplemented $e) {
                        // simply ignore unsupported data/type
                        $formatted = ['base' => null];
                    }
                }
                break;
            case 'ordered':
            case 'multiple':
                if(strlen($value) === 0){
                    $formatted = ['list' => [$var->getBaseType() => []]];
                }else{
                    preg_match_all('/([^\[\];<>]+)/', $value, $matches);
                    $list = [];
                    foreach($matches[1] as $valueString){
                        if(empty(trim($valueString))){
                            continue;
                        }

                        try {
                            $list[] = self::formatStringValue($var->getBaseType(), $valueString);
                        } catch (\common_exception_NotImplemented $e) {
                            // simply ignore unsupported data/type
                        }
                    }
                    $formatted = ['list' => [$var->getBaseType() => $list]];
                }
                break;
            default:
                throw new \common_Exception('unknown response cardinality');
        }
        return $formatted;
    }