code: func (w *Worktree) Submodules() (Submodules, error) {
  	l := make(Submodules, 0)
  	m, err := w.readGitmodulesFile()
  	if err != nil || m == nil {
  		return l, err
  	}
  
  	c, err := w.r.Config()
  	if err != nil {
  		return nil, err
  	}
  
  	for _, s := range m.Submodules {
  		l = append(l, w.newSubmodule(s, c.Submodules[s.Name]))
  	}
  
  	return l, nil
  }
docs: // Submodules returns all the available submodules