rules() as $versionNumber => $attribute) { $currentValue = $container->getAttributeValue($attribute); if ($versionNumber === $currentValue) { return $versionNumber; } } return ''; } public function getFromDOMElement(DOMElement $element): string { return $this->discover(new DomElementContainer($element)); } public function getFromDOMDocument(DOMDocument $document): string { return $this->getFromDOMElement(Xml::documentElement($document)); } public function getFromNode(NodeInterface $node): string { return $this->discover(new NodeContainer($node)); } public function getFromXmlString(string $contents): string { return $this->getFromDOMDocument(Xml::newDocumentContent($contents)); } }