public function invalidate(array $tags)
    {
        $hashes = $this->getHashes($tags);

        // Prefix tags in order to delete them
        foreach ($tags as $key => $tag) {
            $tags[$key] = $this->redis->prefix($tag);
        }

        $this->deleteItems($hashes);
        $this->deleteItems($tags);

        return $hashes;
    }