code: func (a *API) FetchContactGroup(cid CIDType) (*ContactGroup, error) {
  	if cid == nil || *cid == "" {
  		return nil, fmt.Errorf("Invalid contact group CID [none]")
  	}
  
  	groupCID := string(*cid)
  
  	matched, err := regexp.MatchString(config.ContactGroupCIDRegex, groupCID)
  	if err != nil {
  		return nil, err
  	}
  	if !matched {
  		return nil, fmt.Errorf("Invalid contact group CID [%s]", groupCID)
  	}
  
  	result, err := a.Get(groupCID)
  	if err != nil {
  		return nil, err
  	}
  
  	if a.Debug {
  		a.Log.Printf("[DEBUG] fetch contact group, received JSON: %s", string(result))
  	}
  
  	group := new(ContactGroup)
  	if err := json.Unmarshal(result, group); err != nil {
  		return nil, err
  	}
  
  	return group, nil
  }
docs: // FetchContactGroup retrieves contact group with passed cid.