* Returns the number of times {@link Cache} lookup methods have returned either a cached or
   * uncached value. This is defined as {@code hitCount + missCount}.
   *
   * <p><b>Note:</b> the values of the metrics are undefined in case of overflow (though it is
   * guaranteed not to throw an exception). If you require specific handling, we recommend
   * implementing your own stats collector.
   */
  public long requestCount() {

   * Returns the number of times {@link Cache} lookup methods have returned either a cached or
   * uncached value. This is defined as {@code hitCount + missCount}.
   *
   * <p><b>Note:</b> the values of the metrics are undefined in case of overflow (though it is
   * guaranteed not to throw an exception). If you require specific handling, we recommend
   * implementing your own stats collector.
   */
  public long requestCount() {

  /**
   * Returns the package name of {@code clazz} according to the Java Language Specification (section
   * 6.7). Unlike {@link Class#getPackage}, this method only parses the class name, without
   * attempting to define the {@link Package} and hence load files.
   */
  public static String getPackageName(Class<?> clazz) {
    return getPackageName(clazz.getName());
  }

  /**

   *       involving {@code view} will throw)
   *   <li>{@code hashCode()} does not throw
   *   <li>if {@code node} is re-added to the graph after having been removed, {@code view}'s
   *       behavior is undefined
   * </ul>
   *
   * @throws IllegalArgumentException if {@code node} is not an element of this graph
   */
  @Override
  Set<N> adjacentNodes(N node);

  /**

     * {@link #getSource()}, {@link #getLineNumber()} and {@link #getColumnNumber()}. The exact syntax of the returned
     * value is undefined.
     *
     * @return the location of the problem, never {@code null}
     */
    @Nonnull
    String getLocation();

    /**
     * Gets the exception that caused this problem (if any).
     *

   *
   * <pre>{@code
   * b ---- a ---- d
   * |      |
   * |      |
   * e ---- c ---- f
   * }</pre>
   *
   * <p>The behavior of this method is undefined if the nodes, or the topology of the graph, change
   * while iteration is in progress.
   *
   * <p>The returned {@code Iterable} can be iterated over multiple times. Every iterator will

   * contains all elements that are contained in either {@code set1} or {@code set2} but not in
   * both. The iteration order of the returned set is undefined.
   *
   * <p>Results are undefined if {@code set1} and {@code set2} are sets based on different
   * equivalence relations, for example if {@code set1} is a {@link HashSet} and {@code set2} is a

 * Multimaps#synchronizedSetMultimap}.
 *
 * <p><b>Warning:</b> Do not modify either a key <i>or a value</i> of a {@code HashMultimap} in a
 * way that affects its {@link Object#equals} behavior. Undefined behavior and bugs will result.
 *
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible(serializable = true, emulated = true)
@ElementTypesAreNonnullByDefault

    assertThat(edges).hasSize(2);
    assertThat(edges).contains(EndpointPair.ordered(N1, N1));
    assertThat(edges).contains(EndpointPair.ordered(N1, N2));

    // unordered endpoints not OK for directed graph (undefined behavior)
    assertThat(edges).doesNotContain(EndpointPair.unordered(N1, N2));

    assertThat(edges).doesNotContain(EndpointPair.ordered(N2, N1)); // wrong order

    assertThat(edges).hasSize(2);
    assertThat(edges).contains(EndpointPair.ordered(N1, N1));
    assertThat(edges).contains(EndpointPair.ordered(N1, N2));

    // unordered endpoints not OK for directed graph (undefined behavior)
    assertThat(edges).doesNotContain(EndpointPair.unordered(N1, N2));

    assertThat(edges).doesNotContain(EndpointPair.ordered(N2, N1)); // wrong order