code: func (s *Secret) Value(key string) (string, error) {
  	s.Lock()
  	defer s.Unlock()
  
  	if s.data == nil {
  		if !strings.HasPrefix(s.body, "---\n") {
  			return "", store.ErrYAMLNoMark
  		}
  		if err := s.decode(); err != nil {
  			return "", err
  		}
  	}
  	if v, found := s.data[key]; found {
  		return fmt.Sprintf("%v", v), nil
  	}
  	return "", store.ErrYAMLNoKey
  }
docs: // Value returns the value of the given key if the body contained valid
  // YAML