public function load(): void
    {
        try {
            $keys = $this->cache->get(self::INDEXING_KEY);
            if ($keys instanceof Keys) {
                $this->keys = $keys;
                return;
            }
        } catch (CacheException $e) {
            trigger_error($e->getMessage(), E_USER_WARNING);
        }

        $this->keys = new Keys();
    }