private function generateSourceSeo($key)
    {
        if (isset($this->{$key})) {
            return $this->{$key};
        }

        $object = $this;
        foreach (explode('.', $key) as $segment) {
            if (!is_object($object) || !$tmp = $object->{$segment}) {
                return null;
            }

            $object = $object->{$segment};
        }

        return $object;
    }