code: func (a *API) FetchUser(cid CIDType) (*User, error) {
  	var userCID string
  
  	if cid == nil || *cid == "" {
  		userCID = config.UserPrefix + "/current"
  	} else {
  		userCID = string(*cid)
  	}
  
  	matched, err := regexp.MatchString(config.UserCIDRegex, userCID)
  	if err != nil {
  		return nil, err
  	}
  	if !matched {
  		return nil, fmt.Errorf("Invalid user CID [%s]", userCID)
  	}
  
  	result, err := a.Get(userCID)
  	if err != nil {
  		return nil, err
  	}
  
  	if a.Debug {
  		a.Log.Printf("[DEBUG] fetch user, received JSON: %s", string(result))
  	}
  
  	user := new(User)
  	if err := json.Unmarshal(result, user); err != nil {
  		return nil, err
  	}
  
  	return user, nil
  }
docs: // FetchUser retrieves user with passed cid. Pass nil for '/user/current'.