code: func CreateDirectory(prefix string) (*Directory, error) {
  	name, err := ioutil.TempDir("", prefix+"-")
  	if err != nil {
  		return nil, err
  	}
  
  	return &Directory{
  		Name: name,
  	}, nil
  }
docs: // CreateDirectory does create the actual disk directory, and return a
  // new representation of it.