public function is($node)
    {
        if ($node instanceof Element) {
            $node = $node->getNode();
        }

        if (!$node instanceof DOMNode) {
            throw new InvalidArgumentException(sprintf('Argument 1 passed to %s must be an instance of %s or DOMNode, %s given', __METHOD__, __CLASS__, (is_object($node) ? get_class($node) : gettype($node))));
        }

        return $this->node->isSameNode($node);
    }