* equivalence relations, for example if {@code set1} is a {@link HashSet} and {@code set2} is a
   * {@link TreeSet} or the {@link Map#keySet} of an {@code IdentityHashMap}.
   */
  public static <E extends @Nullable Object> SetView<E> difference(Set<E> set1, Set<?> set2) {
    checkNotNull(set1, "set1");
    checkNotNull(set2, "set2");

    return new SetView<E>() {

      Set<? extends E> set1, Set<? extends E> set2) {
    checkNotNull(set1, "set1");
    checkNotNull(set2, "set2");

    return new SetView<E>() {
      @Override
      public int size() {
        int size = set1.size();
        for (E e : set2) {
          if (!set1.contains(e)) {
            size++;
          }
        }
        return size;
      }

  *added_node = node_def;
  EXPECT_EQ(graph_def.DebugString(), graph_def2.DebugString());

  // Look up some nodes by name.
  TF_Operation* neg2 = TF_GraphOperationByName(graph, "neg");
  EXPECT_TRUE(neg == neg2);
  NodeDef node_def2;
  ASSERT_TRUE(GetNodeDef(neg2, &node_def2));
  EXPECT_EQ(node_def.DebugString(), node_def2.DebugString());

  TF_Operation* feed2 = TF_GraphOperationByName(graph, "feed");

        final Map<String, Object> source = new LinkedHashMap<>();
        source.put("title", "Test");
        source.put("content", "Body");
        source.put("cache", "cached");
        source.put("segment", "seg1");
        source.put("host", "example.com");

        final Set<String> excludeFields = Set.of("cache", "segment");
        final String html = new HtmlIndexExportFormatter().format(source, excludeFields);

				"application/x-appleworks",
				"application/x-archive",
				"application/x-arj",
				"application/x-authorware-bin",
				"application/x-authorware-map",
				"application/x-authorware-seg",
				"application/x-bcpio",
				"application/x-berkeley-db",
				"application/x-bibtex-text-file",
				"application/x-bittorrent",
				"application/x-bplist",
				"application/x-bzip",
				"application/x-bzip2",