code: func (api *Client) ArchiveGroupContext(ctx context.Context, group string) error {
  	values := url.Values{
  		"token":   {api.token},
  		"channel": {group},
  	}
  
  	_, err := api.groupRequest(ctx, "groups.archive", values)
  	return err
  }
docs: // ArchiveGroupContext archives a private group