public static function memoize(callable $provider)
    {
        $cache = [];
        return function ($version, $service, $region) use (&$cache, $provider) {
            $key = "($version)($service)($region)";
            if (!isset($cache[$key])) {
                $cache[$key] = $provider($version, $service, $region);
            }
            return $cache[$key];
        };
    }