code: func prettyError(err error) error {
  	// Add this check can prevent the object creation if err is nil.
  	if err == nil {
  		return nil
  	}
  	// If it's grpc's error, make it more user-friendly.
  	if s, ok := status.FromError(err); ok {
  		return fmt.Errorf(s.Message())
  	}
  	// Else return the original error.
  	return err
  }
docs: // prettyError unwraps or rewrites certain errors to make them more user-friendly.