code: func Exists(ctx context.Context, clt client.ImageAPIClient, image string) (bool, error) {
  	_, err := InspectImage(ctx, clt, image)
  	if err != nil {
  		if client.IsErrNotFound(err) {
  			return false, nil
  		}
  		return false, err
  	}
  	return true, nil
  }
docs: // Exists return whether or not the service image already exists