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 =

        new HashMap<E, N>(INNER_CAPACITY, INNER_LOAD_FACTOR));
  }

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

  @LazyInit private transient @Nullable Reference<Multiset<N>> adjacentNodesReference;

  @Override
  public Set<N> adjacentNodes() {

   * can lead to surprising behavior, so serializing the returned list is <b>not recommended</b>.
   * Instead, copy the list using {@link ImmutableList#copyOf(Collection)} (for example), then
   * serialize the copy. Other methods similar to this do not implement serialization at all for
   * this reason.
   *

    if (connections == null) {
      return false;
    }

    // Since views are returned, we need to copy the edges that will be removed.
    // Thus we avoid modifying the underlying view while iterating over it.
    for (E edge : ImmutableList.copyOf(connections.incidentEdges())) {
      removeEdge(edge);
    }
    nodeConnections.remove(node);
    return true;
  }

  @Override

  private static void testReverse(double[] input, double[] expectedOutput) {
    input = Arrays.copyOf(input, input.length);
    Doubles.reverse(input);
    assertThat(input).isEqualTo(expectedOutput);
  }

  private static void testReverse(
      double[] input, int fromIndex, int toIndex, double[] expectedOutput) {
    input = Arrays.copyOf(input, input.length);
    Doubles.reverse(input, fromIndex, toIndex);

  }

  private static void testReverse(long[] input, long[] expectedOutput) {
    input = Arrays.copyOf(input, input.length);
    Longs.reverse(input);
    assertThat(input).isEqualTo(expectedOutput);
  }

  private static void testReverse(long[] input, int fromIndex, int toIndex, long[] expectedOutput) {
    input = Arrays.copyOf(input, input.length);
    Longs.reverse(input, fromIndex, toIndex);

  private static void testReverse(short[] input, short[] expectedOutput) {
    input = Arrays.copyOf(input, input.length);
    Shorts.reverse(input);
    assertThat(input).isEqualTo(expectedOutput);
  }

  private static void testReverse(
      short[] input, int fromIndex, int toIndex, short[] expectedOutput) {
    input = Arrays.copyOf(input, input.length);
    Shorts.reverse(input, fromIndex, toIndex);

      ImmutableBiMap<K, V> bimap = (ImmutableBiMap<K, V>) map;
      // TODO(lowasser): if we need to make a copy of a BiMap because the
      // forward map is a view, don't make a copy of the non-view delegate map
      if (!bimap.isPartialView()) {
        return bimap;
      }
    }
    return copyOf(map.entrySet());
  }

  /**

  // TODO(cpovirk): should we reject null items, since the tests already check null automatically?
  @CanIgnoreReturnValue
  public RelationshipTester<T> addRelatedGroup(Iterable<? extends T> group) {
    groups.add(ImmutableList.copyOf(group));
    return this;
  }

  public void test() {
    for (int groupNumber = 0; groupNumber < groups.size(); groupNumber++) {
      ImmutableList<T> group = groups.get(groupNumber);

    } catch (IOException caught) {
      assertThat(caught).isEqualTo(thrownException);
    }

    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 {