code: func (m *Generator) spawn(genbin string) ([]string, error) {
  	var args []string
  	for k, v := range m.Flags {
  		if k == "debug" {
  			continue
  		}
  		args = append(args, fmt.Sprintf("--%s=%s", k, v))
  	}
  	sort.Strings(args)
  	args = append(args, "--version="+version.String())
  	args = append(args, m.CustomFlags...)
  	cmd := exec.Command(genbin, args...)
  	out, err := cmd.CombinedOutput()
  	if err != nil {
  		return nil, fmt.Errorf("%s\n%s", err, string(out))
  	}
  	res := strings.Split(string(out), "\n")
  	for (len(res) > 0) && (res[len(res)-1] == "") {
  		res = res[:len(res)-1]
  	}
  	return res, nil
  }
docs: // spawn runs the compiled generator using the arguments initialized by Kingpin
  // when parsing the command line.