code: func reportError(stderr io.Writer, name string, str string, withHelp bool) {
  	str = strings.TrimSuffix(str, ".") + "."
  	if withHelp {
  		str += "\nSee '" + os.Args[0] + " " + name + " --help'."
  	}
  	fmt.Fprintf(stderr, "%s: %s\n", os.Args[0], str)
  }
docs: // reportError is a utility method that prints a user-friendly message
  // containing the error that occurred during parsing and a suggestion to get help