code: func initKeysDir(dirPath string) (string, error) {
  	var err error
  	// not specified? use `~/.tsh`
  	if dirPath == "" {
  		u, err := user.Current()
  		if err != nil {
  			dirPath = os.TempDir()
  		} else {
  			dirPath = u.HomeDir
  		}
  		dirPath = filepath.Join(dirPath, defaultKeyDir)
  	}
  	// create if doesn't exist:
  	_, err = os.Stat(dirPath)
  	if err != nil {
  		if os.IsNotExist(err) {
  			err = os.MkdirAll(dirPath, os.ModeDir|profileDirPerms)
  			if err != nil {
  				return "", trace.ConvertSystemError(err)
  			}
  		} else {
  			return "", trace.Wrap(err)
  		}
  	}
  
  	return dirPath, nil
  }
docs: // initKeysDir initializes the keystore root directory. Usually it is ~/.tsh