@Override
  public int add(@ParametricNullness E element, int occurrences) {
    checkNonnegative(occurrences, "occurrences");
    if (occurrences == 0) {
      return count(element);
    }
    checkArgument(range.contains(element));
    AvlNode<E> root = rootReference.get();
    if (root == null) {
      int unused = comparator().compare(element, element);
      AvlNode<E> newRoot = new AvlNode<>(element, occurrences);

      }
      return newCapacity;
    }

    @CanIgnoreReturnValue
    public abstract Builder<E> add(E element);

    @CanIgnoreReturnValue
    public Builder<E> add(E... elements) {
      checkNotNull(elements); // for GWT
      for (E element : elements) {
        add(checkNotNull(element));
      }
      return this;
    }

    @CanIgnoreReturnValue

                    List<Integer> columnKeys = Lists.newArrayList();
                    for (Object element : elements) {
                      @SuppressWarnings("unchecked")
                      Cell<String, Integer, Character> cell =
                          (Cell<String, Integer, Character>) element;
                      columnKeys.add(cell.getColumnKey());
                    }

    try {
      super.testNulls();
    } catch (AssertionFailedError e) {
      assertWithMessage("Method did not throw null pointer OR element not in graph exception.")
          .that(e)
          .hasCauseThat()
          .hasMessageThat()
          .contains(ERROR_ELEMENT_NOT_IN_GRAPH);
    }
  }

    }

    @Override
    public List<@Nullable V> combine(List<@Nullable Present<V>> values) {
      List<@Nullable V> result = newArrayListWithCapacity(values.size());
      for (Present<V> element : values) {
        result.add(element != null ? element.value : null);
      }
      return unmodifiableList(result);
    }
  }

  /** The result of a successful {@code Future}. */

  private M multimap;

  protected M multimap() {
    return multimap;
  }

  /**
   * @return an array of the proper size with {@code null} as the key of the middle element.
   */
  protected Entry<K, V>[] createArrayWithNullKey() {
    Entry<K, V>[] array = createSamplesArray();
    int nullKeyLocation = getNullLocation();
    Entry<K, V> oldEntry = array[nullKeyLocation];

  DescendingImmutableSortedMultiset(ImmutableSortedMultiset<E> forward) {
    this.forward = forward;
  }

  @Override
  public int count(@CheckForNull Object element) {
    return forward.count(element);
  }

  @Override
  @CheckForNull
  public Entry<E> firstEntry() {
    return forward.lastEntry();
  }

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {

  public void testRemove_size1() {
    assertEquals("size1Queue.remove() should return first element", e0(), getQueue().remove());
    expectMissing(e0());
  }

  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)
  public void testRemove_sizeMany() {
    assertEquals("sizeManyQueue.remove() should return first element", e0(), getQueue().remove());
    expectMissing(e0());
  }

  DescendingImmutableSortedMultiset(ImmutableSortedMultiset<E> forward) {
    this.forward = forward;
  }

  @Override
  public int count(@CheckForNull Object element) {
    return forward.count(element);
  }

  @Override
  @CheckForNull
  public Entry<E> firstEntry() {
    return forward.lastEntry();
  }

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {

import java.util.Collection;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.junit.Ignore;

/**
 * Base class for collection testers.
 *
 * @param <E> the element type of the collection to be tested.
 * @author Kevin Bourrillion
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@ElementTypesAreNonnullByDefault