code: func (v *Vserver) AddVIP(vip *seesaw.VIP) error {
  	key := vip.String()
  	if _, ok := v.VIPs[key]; ok {
  		return fmt.Errorf("Vserver %q already contains VIP %q", v.Name, key)
  	}
  	v.VIPs[key] = vip
  	return nil
  }
docs: // AddVIP adds a VIP to a Vserver.