code: func splitVersion(version string) (string, string, error) {
  	var urlSuffix string
  	subs := kubeBucketPrefixes.FindAllStringSubmatch(version, 1)
  	if len(subs) != 1 || len(subs[0]) != 4 {
  		return "", "", errors.Errorf("invalid version %q", version)
  	}
  
  	switch {
  	case strings.HasPrefix(subs[0][2], "ci"):
  		// Just use whichever the user specified
  		urlSuffix = subs[0][2]
  	default:
  		urlSuffix = "release"
  	}
  	url := fmt.Sprintf("%s/%s", kubeReleaseBucketURL, urlSuffix)
  	return url, subs[0][3], nil
  }
docs: // Internal helper: split version parts,
  // Return base URL and cleaned-up version