code: func indent(spaces int, s string) (string, error) {
  	if spaces < 0 {
  		return "", fmt.Errorf("indent value must be a positive integer")
  	}
  	var output, prefix []byte
  	var sp bool
  	var size int
  	prefix = []byte(strings.Repeat(" ", spaces))
  	sp = true
  	for _, c := range []byte(s) {
  		if sp && c != '\n' {
  			output = append(output, prefix...)
  			size += spaces
  		}
  		output = append(output, c)
  		sp = c == '\n'
  		size++
  	}
  	return string(output[:size]), nil
  }
docs: // Indent prefixes each line of a string with the specified number of spaces