code: func (c *Cluster) AddVLAN(vlan *seesaw.VLAN) error {
  	key := vlan.Key()
  	if _, ok := c.VLANs[key]; ok {
  		return fmt.Errorf("Cluster %q already contains VLAN %q", c.Site, key)
  	}
  	c.VLANs[key] = vlan
  	return nil
  }
docs: // AddVLAN adds a VLAN to a Seesaw Cluster.