public static <K extends Comparable, V extends Comparable> TreeMultimap<K, V> create() {
    return new TreeMultimap<>(Ordering.natural(), Ordering.natural());
  }

  /**
   * Creates an empty {@code TreeMultimap} instance using explicit comparators. Neither comparator
   * may be null; use {@link Ordering#natural()} to specify natural order.
   *

/**
 * Test {@code TreeMultimap.asMap().subMap()} with {@link MapInterfaceTest}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public class SubMapMultimapAsMapImplementsMapTest extends AbstractMultimapAsMapImplementsMapTest {

  public SubMapMultimapAsMapImplementsMapTest() {
    super(true, true, true);
  }

  private TreeMultimap<String, Integer> createMultimap() {

/**
 * Test {@code TreeMultimap.asMap().subMap()} with {@link MapInterfaceTest}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public class SubMapMultimapAsMapImplementsMapTest extends AbstractMultimapAsMapImplementsMapTest {

  public SubMapMultimapAsMapImplementsMapTest() {
    super(true, true, true);
  }

  private TreeMultimap<String, Integer> createMultimap() {

  private SetMultimap<String, Integer> create() {
    return TreeMultimap.create(StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);
  }

  /** Create and populate a {@code TreeMultimap} with explicit comparators. */
  private TreeMultimap<@Nullable String, @Nullable Integer> createPopulate() {
    TreeMultimap<@Nullable String, @Nullable Integer> multimap =
        TreeMultimap.create(StringLength.COMPARATOR, DECREASING_INT_COMPARATOR);

import java.util.SortedMap;
import java.util.SortedSet;
import org.jspecify.annotations.Nullable;

/**
 * Basic implementation of a {@link SortedSetMultimap} with a sorted key set.
 *
 * <p>This superclass allows {@code TreeMultimap} to override methods to return navigable set and
 * map types in non-GWT only, while GWT code will inherit the SortedMap/SortedSet overrides.
 *
 * @author Louis Wasserman
 */
@GwtCompatible

  public void testUnmodifiableTreeMultimap() {
    checkUnmodifiableMultimap(TreeMultimap.<String, Integer>create(), false, "null", 42);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testSerializingUnmodifiableTreeMultimap() {
    Multimap<String, Integer> unmodifiable =
        prepareUnmodifiableTests(TreeMultimap.<String, Integer>create(), false, "null", 42);

import java.util.SortedMap;
import java.util.SortedSet;
import org.jspecify.annotations.Nullable;

/**
 * Basic implementation of a {@link SortedSetMultimap} with a sorted key set.
 *
 * <p>This superclass allows {@code TreeMultimap} to override methods to return navigable set and
 * map types in non-GWT only, while GWT code will inherit the SortedMap/SortedSet overrides.
 *
 * @author Louis Wasserman
 */
@GwtCompatible

import com.google.common.collect.SortedSetMultimap;
import com.google.common.collect.Table;
import com.google.common.collect.Tables;
import com.google.common.collect.TreeBasedTable;
import com.google.common.collect.TreeMultimap;
import com.google.common.io.ByteSink;
import com.google.common.io.ByteSource;
import com.google.common.io.ByteStreams;
import com.google.common.io.CharSink;
import com.google.common.io.CharSource;

import com.google.common.collect.SortedSetMultimap;
import com.google.common.collect.Table;
import com.google.common.collect.Tables;
import com.google.common.collect.TreeBasedTable;
import com.google.common.collect.TreeMultimap;
import com.google.common.io.ByteSink;
import com.google.common.io.ByteSource;
import com.google.common.io.ByteStreams;
import com.google.common.io.CharSink;
import com.google.common.io.CharSource;

                CollectionSize.ANY)
            .createTestSuite());
    suite.addTestSuite(HashMultimapTest.class);
    return suite;
  }

  /*
   * The behavior of toString() is tested by TreeMultimap, which shares a
   * lot of code with HashMultimap and has deterministic iteration order.
   */
  public void testCreate() {
    HashMultimap<String, Integer> multimap = HashMultimap.create();
    multimap.put("foo", 1);