FluentDOM\Nodes\Modifier::insertChildrenBefore PHP Method

    public function insertChildrenBefore($contentNodes)
    {
        $result = array();
        if ($this->_node instanceof \DOMElement) {
            if ($this->_node->firstChild instanceof \DOMNode) {
                $result = (new self($this->_node->firstChild))->insertNodesBefore($contentNodes);
            } else {
                $result = self::appendChildren($contentNodes);
            }
        }
        return $result;
    }