code: public List<Node> getConnectedNodes() {
          List<Node> nodes = new ArrayList<>();
          for (Link l : links) {
              if (l.getElement() instanceof Node) {
                  nodes.add((Node) l.getElement());
              }
          }
          return nodes;
      }
docs: Get the full list of nodes that have been connected into the network
  
  @return the list of nodes