public function after($content)
    {
        $content = self::create($content);
        $newnodes = array();
        foreach ($this as $i => $node) {
            /** @var \DOMNode $node */
            $refnode = $node->nextSibling;
            foreach ($content as $newnode) {
                /** @var \DOMNode $newnode */
                $newnode = static::importNewnode($newnode, $node, $i);
                if ($refnode === null) {
                    $node->parentNode->appendChild($newnode);
                } else {
                    $node->parentNode->insertBefore($newnode, $refnode);
                }
                $newnodes[] = $newnode;
            }
        }
        $content->clear();
        $content->add($newnodes);
        return $this;
    }