code: func (api *Client) RenameGroupContext(ctx context.Context, group, name string) (*Channel, error) {
  	values := url.Values{
  		"token":   {api.token},
  		"channel": {group},
  		"name":    {name},
  	}
  
  	// XXX: the created entry in this call returns a string instead of a number
  	// so I may have to do some workaround to solve it.
  	response, err := api.groupRequest(ctx, "groups.rename", values)
  	if err != nil {
  		return nil, err
  	}
  	return &response.Channel, nil
  }
docs: // RenameGroupContext renames a group with a custom context