public function score($member)
    {
        $ret = $this->redis->zscore($this->key, $this->valToStr($member));
        if ($ret === null) {
            return null;
        }

        return $this->strToVal($ret);
    }
public function score($member)
    {
        $ret = $this->redis->zscore($this->key, $this->valToStr($member));
        if ($ret === null) {
            return null;
        }

        return $this->strToVal($ret);
    }
@link https://redis.io/commands/zscore

@param string|number $member

@return null|number|string