_keyFromItemTags example

$lifetime = $this->getLifetime($specificLifetime);

        if (!$tags || !count($tags)) {
            $tags = [''];
        }
        if (is_string($tags)) {
            $tags = [$tags];
        }

        if (!count($tags)) {
            $this->_redis->del($this->_keyFromItemTags($id));
            if ($lifetime === null) {
                $return = $this->_redis->set($this->_keyFromId($id), $data);
            } else {
                $return = $this->_redis->setex($this->_keyFromId($id), $lifetime, $data);
            }
            $this->_redis->sAdd($this->_keyFromItemTags($id), '');
            if ($lifetime !== null) {
                $this->_redis->expire($this->_keyFromItemTags($id), $lifetime);
            } else {
                $redis = $this->_redis->persist($this->_keyFromItemTags($id));
            }