public function getImporterXsd(): string
    {
        $xsd = new \DOMDocument('1.0', 'utf-8');
        $xsd->loadXML('<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"/>');
        foreach ($this->schemas as $schema) {
            $node = $xsd->createElementNS('http://www.w3.org/2001/XMLSchema', 'import');
            $node->setAttribute('namespace', $schema->getNamespace());
            $node->setAttribute('schemaLocation', str_replace('\\', '/', $schema->getLocation()));
            $xsd->documentElement->appendChild($node);
        }
        return $xsd->saveXML();
    }