@Override
        @Nullable String chop(String str) {
          String result = i.chop(str);
          return result != null ? result : you.chop(str);
        }
      };
    }

    abstract @Nullable String chop(String str);

    static Chopper suffix(String suffix) {
      return new Chopper() {
        @Override
        @Nullable String chop(String str) {
          if (str.endsWith(suffix)) {

        @Override
        @Nullable String chop(String str) {
          String result = i.chop(str);
          return result != null ? result : you.chop(str);
        }
      };
    }

    abstract @Nullable String chop(String str);

    static Chopper suffix(String suffix) {
      return new Chopper() {
        @Override
        @Nullable String chop(String str) {
          if (str.endsWith(suffix)) {

 * // Building a mutable value graph
 * MutableValueGraph<String, Double> graph =
 *     ValueGraphBuilder.undirected().allowsSelfLoops(true).build();
 * graph.putEdgeValue("San Francisco", "San Francisco", 0.0);
 * graph.putEdgeValue("San Jose", "San Jose", 0.0);
 * graph.putEdgeValue("San Francisco", "San Jose", 48.4);
 *
 * // Building an immutable value graph
 * ImmutableValueGraph<String, Double> immutableGraph =

 * <p>Examples of use:
 *
 * {@snippet :
 * // Building a mutable graph
 * MutableGraph<String> graph = GraphBuilder.undirected().allowsSelfLoops(true).build();
 * graph.putEdge("bread", "bread");
 * graph.putEdge("chocolate", "peanut butter");
 * graph.putEdge("peanut butter", "jelly");
 *
 * // Building an immutable graph
 * ImmutableGraph<String> immutableGraph =
 *     GraphBuilder.undirected()
 *         .allowsSelfLoops(true)

 * as a {@code List}:
 *
 * {@snippet :
 * ImmutableList<String> results =
 *     FluentIterable.from(database.getClientList())
 *         .filter(Client::isActiveInLastMonth)
 *         .transform(Object::toString)
 *         .limit(10)
 *         .toList();
 * }
 *
 * The approximate stream equivalent is:
 *
 * {@snippet :
 * List<String> results =
 *     database.getClientList()
 *         .stream()

 * as a {@code List}:
 *
 * {@snippet :
 * ImmutableList<String> results =
 *     FluentIterable.from(database.getClientList())
 *         .filter(Client::isActiveInLastMonth)
 *         .transform(Object::toString)
 *         .limit(10)
 *         .toList();
 * }
 *
 * The approximate stream equivalent is:
 *
 * {@snippet :
 * List<String> results =
 *     database.getClientList()
 *         .stream()

 * factory classes like:
 *
 * <pre>
 * interface Book {...}
 * public class Books {
 *   public static Book hardcover(String title) {...}
 *   public static Book paperback(String title) {...}
 * }
 * </pre>
 *
 * <p>And all the created {@code Book} instances can be tested with:
 *
 * <pre>
 * new ClassSanityTester()

 *
 * {@snippet :
 * // Building a mutable network
 * MutableNetwork<String, Integer> network =
 *     NetworkBuilder.directed().allowsParallelEdges(true).build();
 * flightNetwork.addEdge("LAX", "ATL", 3025);
 * flightNetwork.addEdge("LAX", "ATL", 1598);
 * flightNetwork.addEdge("ATL", "LAX", 2450);
 *
 * // Building a immutable network
 * ImmutableNetwork<String, Integer> immutableNetwork =
 *     NetworkBuilder.directed()

      checkNotNull(node);
      throw new IllegalArgumentException(String.format(NODE_NOT_IN_GRAPH, node));
    }
    return connections;
  }

  final N checkedReferenceNode(E edge) {
    N referenceNode = edgeToReferenceNode.get(edge);
    if (referenceNode == null) {
      checkNotNull(edge);
      throw new IllegalArgumentException(String.format(EDGE_NOT_IN_GRAPH, edge));
    }
    return referenceNode;
  }