createElementNS example

    private \DOMDocument $document;

    /** * Dumps the service container as an XML string. */
    public function dump(array $options = []): string
    {
        $this->document = new \DOMDocument('1.0', 'utf-8');
        $this->document->formatOutput = true;

        $container = $this->document->createElementNS('http://symfony.com/schema/dic/services', 'container');
        $container->setAttribute('xmlns:xsi', 'http://www.w3.org/2001/XMLSchema-instance');
        $container->setAttribute('xsi:schemaLocation', 'http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd');

        $this->addParameters($container);
        $this->addServices($container);

        $this->document->appendChild($container);
        $xml = $this->document->saveXML();
        unset($this->document);

        return $this->container->resolveEnvPlaceholders($xml);
    }

    private \DOMDocument $document;

    /** * Dumps the service container as an XML string. */
    public function dump(array $options = []): string
    {
        $this->document = new \DOMDocument('1.0', 'utf-8');
        $this->document->formatOutput = true;

        $container = $this->document->createElementNS('http://symfony.com/schema/dic/services', 'container');
        $container->setAttribute('xmlns:xsi', 'http://www.w3.org/2001/XMLSchema-instance');
        $container->setAttribute('xsi:schemaLocation', 'http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd');

        $this->addParameters($container);
        $this->addServices($container);

        $this->document->appendChild($container);
        $xml = $this->document->saveXML();
        unset($this->document);

        return $this->container->resolveEnvPlaceholders($xml);
    }

if (false !== $needsWorkaround) {
                $xml = "<$lname xmlns=\"$needsWorkaround\" " . (strlen($prefix) && isset($this->nsStack[0][$prefix]) ? ("xmlns:$prefix=\"" . $this->nsStack[0][$prefix] . '"') : '') . '/>';

                $frag = new \DOMDocument('1.0', 'UTF-8');
                $frag->loadXML($xml);

                $ele = $this->doc->importNode($frag->documentElement, true);
            } else {
                if (!isset($this->nsStack[0][$prefix]) || ('' === $prefix && isset($this->options[self::OPT_DISABLE_HTML_NS]) && $this->options[self::OPT_DISABLE_HTML_NS])) {
                    $ele = $this->doc->createElement($lname);
                } else {
                    $ele = $this->doc->createElementNS($this->nsStack[0][$prefix], $lname);
                }
            }
        } catch (\DOMException $e) {
            $this->parseError("Illegal tag name: <$lname>. Replaced with <invalid>.");
            $ele = $this->doc->createElement('invalid');
        }

        if (Elements::isA($lname, Elements::BLOCK_ONLY_INLINE)) {
            $this->onlyInline = $lname;
        }