code: func randomString(length int) (string, error) {
  	randBytes := make([]byte, length)
  
  	if n, err := randomReader.Read(randBytes); err != nil || n != length {
  		if err == nil {
  			err = fmt.Errorf("only got %v random bytes, expected %v", n, length)
  		}
  		return "", fmt.Errorf("unable to generate random string: %v", err)
  	}
  
  	return hex.EncodeToString(randBytes), nil
  }
docs: // randomString returns a random hex string.