FluentDOM\Node\NonDocumentTypeChildNode\Properties::__set PHP Метод

    public function __set($name, $value)
    {
        switch ($name) {
            case 'nextElementSibling':
            case 'previousElementSibling':
                throw new \BadMethodCallException(sprintf('Can not write readonly property %s::$%s.', get_class($this), $name));
        }
        $this->setParentProperty($name, $value);
    }