checkNotNull(edge);
    checkNotNull(node);

    if (isSelfLoop) {
      checkPositive(++selfLoopCount);
    }
    N previousNode = inEdgeMap.put(edge, node);
    checkState(previousNode == null);
  }

  @Override
  public void addOutEdge(E edge, N node) {
    checkNotNull(edge);
    checkNotNull(node);

    N previousNode = outEdgeMap.put(edge, node);

      @ParametricNullness E key,
      Comparator<? super E> comparator,
      KeyPresentBehavior presentBehavior,
      KeyAbsentBehavior absentBehavior) {
    checkNotNull(comparator);
    checkNotNull(list);
    checkNotNull(presentBehavior);
    checkNotNull(absentBehavior);
    if (!(list instanceof RandomAccess)) {
      list = new ArrayList<>(list);
    }

  }

  @Override
  public boolean hasEdgeConnecting(N nodeU, N nodeV) {
    checkNotNull(nodeU);
    checkNotNull(nodeV);
    return nodes().contains(nodeU) && successors(nodeU).contains(nodeV);
  }

  @Override
  public boolean hasEdgeConnecting(EndpointPair<N> endpoints) {
    checkNotNull(endpoints);
    if (!isOrderingCompatible(endpoints)) {
      return false;
    }

   */
  public static <T extends @Nullable Object> Predicate<T> and(
      Predicate<? super T> first, Predicate<? super T> second) {
    return new AndPredicate<>(Predicates.<T>asList(checkNotNull(first), checkNotNull(second)));
  }

  /**
   * Returns a predicate that evaluates to {@code true} if any one of its components evaluates to

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.Executors.newCachedThreadPool;
import static java.util.concurrent.TimeUnit.SECONDS;
import static junit.framework.Assert.assertEquals;

   */
  SubscriberExceptionContext(
      EventBus eventBus, Object event, Object subscriber, Method subscriberMethod) {
    this.eventBus = checkNotNull(eventBus);
    this.event = checkNotNull(event);
    this.subscriber = checkNotNull(subscriber);
    this.subscriberMethod = checkNotNull(subscriberMethod);
  }

  /**
   * @return The {@link EventBus} that handled the event and the subscriber. Useful for broadcasting

    this.singleRowKey = checkNotNull(rowKey);
    this.singleColumnKey = checkNotNull(columnKey);
    this.singleValue = checkNotNull(value);
  }

  SingletonImmutableTable(Cell<R, C, V> cell) {
    this(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
  }

  @Override
  public ImmutableMap<R, V> column(C columnKey) {
    checkNotNull(columnKey);
    return containsColumn(columnKey)

  }

  @Override
  public T or(T defaultValue) {
    checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
    return reference;
  }

  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    checkNotNull(secondChoice);
    return this;
  }

  @Override
  public T or(Supplier<? extends T> supplier) {
    checkNotNull(supplier);
    return reference;
  }

  @Override

  // be (optionally) be combined with another if needed (with something like
  // MultiplexingOutputStream).
  public HashingOutputStream(HashFunction hashFunction, OutputStream out) {
    super(checkNotNull(out));
    this.hasher = checkNotNull(hashFunction.newHasher());
  }

  @Override
  public void write(int b) throws IOException {
    hasher.putByte((byte) b);
    out.write(b);
  }

  @Override

    @Override
    public SortedMap<C, V> subMap(C fromKey, C toKey) {
      checkArgument(rangeContains(checkNotNull(fromKey)) && rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, fromKey, toKey);
    }

    @Override
    public SortedMap<C, V> headMap(C toKey) {
      checkArgument(rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, lowerBound, toKey);
    }

    @Override