public function getSortedIndex($key, $reverse = false, $start = null, $stop = null)
{
if ($reverse) {
return $this->clientCmd('zrevrange', [$key, $start === null ? 0 : $start, $stop === null ? -1 : $stop]);
} else {
return $this->clientCmd('zrange', [$key, $start === null ? 0 : $start, $stop === null ? -1 : $stop]);
}
}