code: func findClusterIDs(tags []*ec2.Tag) (string, string, error) {
  	legacyClusterID := ""
  	newClusterID := ""
  
  	for _, tag := range tags {
  		tagKey := aws.StringValue(tag.Key)
  		if strings.HasPrefix(tagKey, TagNameKubernetesClusterPrefix) {
  			id := strings.TrimPrefix(tagKey, TagNameKubernetesClusterPrefix)
  			if newClusterID != "" {
  				return "", "", fmt.Errorf("Found multiple cluster tags with prefix %s (%q and %q)", TagNameKubernetesClusterPrefix, newClusterID, id)
  			}
  			newClusterID = id
  		}
  
  		if tagKey == TagNameKubernetesClusterLegacy {
  			id := aws.StringValue(tag.Value)
  			if legacyClusterID != "" {
  				return "", "", fmt.Errorf("Found multiple %s tags (%q and %q)", TagNameKubernetesClusterLegacy, legacyClusterID, id)
  			}
  			legacyClusterID = id
  		}
  	}
  
  	return legacyClusterID, newClusterID, nil
  }
docs: // Extracts the legacy & new cluster ids from the given tags, if they are present
  // If duplicate tags are found, returns an error