code: func (t *Topology) addID(nodeID string) bool {
  	t.mu.Lock()
  	defer t.mu.Unlock()
  	if t.containsID(nodeID) {
  		return false
  	}
  	t.nodeIDs = append(t.nodeIDs, nodeID)
  
  	sort.Slice(t.nodeIDs,
  		func(i, j int) bool {
  			return t.nodeIDs[i] < t.nodeIDs[j]
  		})
  
  	return true
  }
docs: // addID adds the node ID to the topology and returns true if added.