}

  static <N, E> UndirectedNetworkConnections<N, E> ofImmutable(Map<E, N> incidentEdges) {
    return new UndirectedNetworkConnections<>(ImmutableBiMap.copyOf(incidentEdges));
  }

  @Override
  public Set<N> adjacentNodes() {
    return Collections.unmodifiableSet(((BiMap<E, N>) incidentEdgeMap).values());
  }

  @Override
  public Set<E> edgesConnecting(N node) {

    checkNotNull(valueFunction);
    checkNotNull(mergeFunction);
    return Collectors.collectingAndThen(
        Collectors.toMap(keyFunction, valueFunction, mergeFunction, LinkedHashMap::new),
        ImmutableMap::copyOf);
  }

  @SuppressWarnings("unchecked") // An empty map works for all types.
  public static <K, V> ImmutableMap<K, V> of() {
    return (ImmutableMap<K, V>) RegularImmutableMap.EMPTY;
  }

    } catch (IOException expected) {
      assertSame(thrownException, expected);
    }

    assertTrue(c1.isClosed());
    assertTrue(c2.isClosed());

    ImmutableSet<Throwable> suppressed = ImmutableSet.copyOf(thrownException.getSuppressed());
    assertEquals(2, suppressed.size());

    assertEquals(ImmutableSet.of(c1Exception, c2Exception), suppressed);
  }

  public void testNullCloseable() throws IOException {

          if (!identifiers.containsKey(ident)) {
            identifiers.put(ident, method);
          }
        }
      }
    }
    return ImmutableList.copyOf(identifiers.values());
  }

  /** Global cache of classes to their flattened hierarchy of supertypes. */
  private static final LoadingCache<Class<?>, ImmutableSet<Class<?>>> flattenHierarchyCache =

          assertEquals(expected.asDescendingMapOfRanges(), subRangeMap.asDescendingMapOfRanges());
          assertEquals(
              ImmutableList.copyOf(subRangeMap.asMapOfRanges().entrySet()).reverse(),
              ImmutableList.copyOf(subRangeMap.asDescendingMapOfRanges().entrySet()));

          if (!expected.asMapOfRanges().isEmpty()) {
            assertEquals(expected.span(), subRangeMap.span());
          }

   */
  public static <N> ImmutableSet<N> reachableNodes(Graph<N> graph, N node) {
    checkArgument(graph.nodes().contains(node), NODE_NOT_IN_GRAPH, node);
    return ImmutableSet.copyOf(Traverser.forGraph(graph).breadthFirst(node));
  }

  // Graph mutation methods

  // Graph view methods

  /**

   */
  public static <N> ImmutableSet<N> reachableNodes(Graph<N> graph, N node) {
    checkArgument(graph.nodes().contains(node), NODE_NOT_IN_GRAPH, node);
    return ImmutableSet.copyOf(Traverser.forGraph(graph).breadthFirst(node));
  }

  // Graph mutation methods

  // Graph view methods

  /**

        to.context = from.context;
        if (from.hashesExternal) {
            to.hashesExternal = true;
            to.ansiHash = from.ansiHash != null ? Arrays.copyOf(from.ansiHash, from.ansiHash.length) : null;
            to.unicodeHash = from.unicodeHash != null ? Arrays.copyOf(from.unicodeHash, from.unicodeHash.length) : null;
        } else {
            NtlmPasswordAuthenticator.cloneInternal(to, from);
        }
    }

    /**

            op.setup(form -> {
                duplicateHostService.getDuplicateHost(id).ifPresent(entity -> {
                    copyBeanToBean(entity, form, copyOp -> {
                        copyOp.excludeNull();
                    });
                    form.crudMode = crudMode;
                }).orElse(() -> {

    return this;
  }

  @CanIgnoreReturnValue
  public EquivalenceTester<T> addEquivalenceGroup(Iterable<T> group) {
    delegate.addRelatedGroup(group);
    items.addAll(ImmutableList.copyOf(group));
    return this;
  }

  /** Run tests on equivalence methods, throwing a failure on an invalid test */
  @CanIgnoreReturnValue
  public EquivalenceTester<T> test() {