/**
   * Returns the entry of the first element in this multiset, or {@code null} if this multiset is
   * empty.
   */
  @Nullable Entry<E> firstEntry();

  /**
   * Returns the entry of the last element in this multiset, or {@code null} if this multiset is
   * empty.
   */
  @Nullable Entry<E> lastEntry();

  /**
   * Returns and removes the entry associated with the lowest element in this multiset, or returns

import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * Implementation for {@link FilteredMultimap#values()}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class FilteredMultimapValues<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractCollection<V> {
  @Weak private final FilteredMultimap<K, V> multimap;

    @Nullable Segment<K, V, E, S> currentSegment;
    @Nullable AtomicReferenceArray<E> currentTable;
    @Nullable E nextEntry;
    @Nullable WriteThroughEntry nextExternal;
    @Nullable WriteThroughEntry lastReturned;

    HashIterator() {
      nextSegmentIndex = segments.length - 1;
      nextTableIndex = -1;
      advance();
    }

    @Override
    public abstract T next();

import org.jspecify.annotations.Nullable;

/**
 * Derived suite generators, split out of the suite builders so that they are available to GWT.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public final class DerivedCollectionGenerators {
  public static class MapEntrySetGenerator<K extends @Nullable Object, V extends @Nullable Object>

   */
  static @Nullable String emptyToNull(@Nullable String string) {
    return stringIsNullOrEmpty(string) ? null : string;
  }

  static String lenientFormat(
      @Nullable String template, @Nullable Object @Nullable ... args) {
    return Strings.lenientFormat(template, args);
  }

  static String stringValueOf(@Nullable Object o) {
    return String.valueOf(o);
  }

     * @param <U> the type returned by the function
     */
    public interface ClosingFunction5<
        V1 extends @Nullable Object,
        V2 extends @Nullable Object,
        V3 extends @Nullable Object,
        V4 extends @Nullable Object,
        V5 extends @Nullable Object,
        U extends @Nullable Object> {
      /**
       * Applies this function to five inputs, or throws an exception if unable to do so.
       *

                "Constructor com.example.Source(java.lang.String): Parameter 0 nullability changed from non-nullable to nullable",
                "Method com.example.SourceKt.invoke(com.example.Source,java.lang.String): Parameter 1 nullability changed from non-nullable to nullable"
            )
            assertHasNoInformation()
        }
    }

 * invoke methods, they invoke methods on the {@code ForwardingSetMultimap}.
 *
 * @author Kurt Alfred Kluever
 * @since 3.0
 */
@GwtCompatible
public abstract class ForwardingSetMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingMultimap<K, V> implements SetMultimap<K, V> {
  /** Constructor for use by subclasses. */
  public ForwardingSetMultimap() {}

  @Override

  private final boolean hasLowerBound;
  private final @Nullable T lowerEndpoint;
  private final BoundType lowerBoundType;
  private final boolean hasUpperBound;
  private final @Nullable T upperEndpoint;
  private final BoundType upperBoundType;

  private GeneralRange(
      Comparator<? super T> comparator,
      boolean hasLowerBound,
      @Nullable T lowerEndpoint,
      BoundType lowerBoundType,

   * a good policy, especially because, in order for the test to pass, the
   * parameter must be misleadingly annotated as @Nullable. I suspect that
   * we'll want to remove @Nullable, add an eager checkNotNull, and loosen up
   * testRemove_nullAllowed.
   */
  @CanIgnoreReturnValue
  @Override
  public int remove(@Nullable Object element, int occurrences) {
    if (occurrences == 0) {
      return count(element);
    }