public function indexExists(int $index): bool
    {
        return $this->redis->lindex($this->key, $index) !== self::RESPONSE_NIL;
    }
public function indexExists(int $index): bool
    {
        return $this->redis->lindex($this->key, $index) !== self::RESPONSE_NIL;
    }
@param int $index The index to look for.

@return bool True if index exists. Will always return true if $index is smaller than length.