code: func (w *Worktree) Clean(opts *CleanOptions) error {
  	s, err := w.Status()
  	if err != nil {
  		return err
  	}
  
  	root := ""
  	files, err := w.Filesystem.ReadDir(root)
  	if err != nil {
  		return err
  	}
  	return w.doClean(s, opts, root, files)
  }
docs: // Clean the worktree by removing untracked files.
  // An empty dir could be removed - this is what  `git clean -f -d .` does.