* silently {@link #addNode(Object) add} {@code nodeU} and {@code nodeV} to the graph.
     *
     * @return this {@code Builder} object
     * @throws IllegalArgumentException if the introduction of the edge would violate {@link
     *     #allowsSelfLoops()}
     */
    @CanIgnoreReturnValue
    public Builder<N> putEdge(N nodeU, N nodeV) {
      mutableGraph.putEdge(nodeU, nodeV);
      return this;
    }

    /**

     * @throws IllegalArgumentException if {@code edge} already exists in the network and does not
     *     connect {@code nodeU} to {@code nodeV}
     * @throws IllegalArgumentException if the introduction of the edge would violate {@link
     *     #allowsParallelEdges()} or {@link #allowsSelfLoops()}
     */
    @CanIgnoreReturnValue
    public ImmutableNetwork.Builder<N, E> addEdge(N nodeU, N nodeV, E edge) {

 * natural ordering of the elements, if there is no comparator) to test element equality. As a
 * result, if the comparator is not consistent with equals, some of the standard implementations may
 * violate the {@code Set} contract.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be
 * thread-safe, even when all of the methods that they depend on are thread-safe.
 *

 *
 * <p><b>Warning:</b> The comparison must be <i>consistent with equals</i> as explained by the
 * {@link Comparable} class specification. Otherwise, the resulting multiset will violate the {@link
 * Collection} contract, which is specified in terms of {@link Object#equals}.
 *
 * <p>See the Guava User Guide article on <a href=

 * natural ordering of the elements, if there is no comparator) to test element equality. As a
 * result, if the comparator is not consistent with equals, some of the standard implementations may
 * violate the {@code Set} contract.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be
 * thread-safe, even when all of the methods that they depend on are thread-safe.
 *

 * elements, if there is no comparator) to test element equality. As a result, if the comparator is
 * not consistent with equals, some of the standard implementations may violate the {@code Set}
 * contract.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be
 * thread-safe, even when all of the methods that they depend on are thread-safe.
 *

 * equivalence of instances.
 *
 * <p><b>Warning:</b> The comparison must be <i>consistent with equals</i> as explained by the
 * {@link Comparable} class specification. Otherwise, the resulting multiset will violate the {@link
 * java.util.Collection} contract, which is specified in terms of {@link Object#equals}.
 *
 * <p>See the Guava User Guide article on <a href=

   * @throws IllegalArgumentException if {@code edge} already exists in the graph and does not
   *     connect {@code nodeU} to {@code nodeV}
   * @throws IllegalArgumentException if the introduction of the edge would violate {@link
   *     #allowsParallelEdges()} or {@link #allowsSelfLoops()}
   */
  @CanIgnoreReturnValue
  boolean addEdge(N nodeU, N nodeV, E edge);

  /**

  }

  public void testCompound_instance() {
    Comparator<String> comparator = byCharAt(1).compound(byCharAt(0));
    Helpers.testComparator(
        comparator,
        ImmutableList.of("red", "yellow", "violet", "blue", "indigo", "green", "orange"));
  }

  public void testCompound_instance_generics() {
    Ordering<Object> objects = Ordering.explicit((Object) 1);
    Ordering<Number> numbers = Ordering.explicit((Number) 1);

  }

  public void testCompound_instance() {
    Comparator<String> comparator = byCharAt(1).compound(byCharAt(0));
    Helpers.testComparator(
        comparator,
        ImmutableList.of("red", "yellow", "violet", "blue", "indigo", "green", "orange"));
  }

  public void testCompound_instance_generics() {
    Ordering<Object> objects = Ordering.explicit((Object) 1);
    Ordering<Number> numbers = Ordering.explicit((Number) 1);