code: func (a *AddrManager) AddLocalAddress(na *wire.NetAddress, priority AddressPriority) error {
  	if !IsRoutable(na) {
  		return fmt.Errorf("address %s is not routable", na.IP)
  	}
  
  	a.lamtx.Lock()
  	defer a.lamtx.Unlock()
  
  	key := NetAddressKey(na)
  	la, ok := a.localAddresses[key]
  	if !ok || la.score < priority {
  		if ok {
  			la.score = priority + 1
  		} else {
  			a.localAddresses[key] = &localAddress{
  				na:    na,
  				score: priority,
  			}
  		}
  	}
  	return nil
  }
docs: // AddLocalAddress adds na to the list of known local addresses to advertise
  // with the given priority.