code: func (c *RadioGroup) SelectItem(r *Radio) bool {
  	found := false
  
  	for _, item := range c.items {
  		if item == r {
  			found = true
  			item.SetSelected(true)
  		} else {
  			item.SetSelected(false)
  		}
  	}
  
  	return found
  }
docs: // SelectItem makes the radio selected. The function returns false
  // if it failed to find the radio in the radio group