* the result of applying {@code countFunction} to the inputs.
   *
   * <p>If the mapped elements contain duplicates (according to {@link Object#equals}), the first
   * occurrence in encounter order appears in the resulting multiset, with count equal to the sum of
   * the outputs of {@code countFunction.applyAsInt(t)} for each {@code t} mapped to that element.
   *
   * @since 22.0
   */
  public static <T extends @Nullable Object, E>

   * inputs, with counts equal to the result of applying {@code countFunction} to the inputs.
   * Elements are added in encounter order.
   *
   * <p>If the mapped elements contain duplicates (according to {@link Object#equals}), the element
   * will be added more than once, with the count summed over all appearances of the element.
   *

 * #iterator()} method after the first, and whose iterator is always unmodifiable.
 *
 * <p>The {@code Iterable} specification does not make it absolutely clear what should happen on a
 * second invocation, so implementors have made various choices, including:
 *
 * <ul>
 *   <li>returning the same iterator again
 *   <li>throwing an exception of some kind

                getKeyForNullValue(),
                v3(),
                (oldV, newV) -> {
                  throw new AssertionFailedError(
                      "Should not call merge function if key was mapped to null");
                }));
    expectReplacement(entry(getKeyForNullValue(), v3()));
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  public void testMergeAbsentNullKey() {
    assertEquals(

import java.util.Comparator;
import java.util.Iterator;
import java.util.NavigableSet;
import java.util.SortedSet;
import java.util.TreeSet;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A wrapper around {@code TreeSet} that aggressively checks to see if elements are mutually
 * comparable. This implementation passes the navigable set test suites.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible

   * cached value, which will be recalculated when {@code get()} is called on the reserialized
   * instance. The actual memoization does not happen when the underlying delegate throws an
   * exception.
   *
   * <p>When the underlying delegate throws an exception then this memoizing supplier will keep
   * delegating calls until it returns valid data.
   *

import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A wrapper around {@code TreeMap} that aggressively checks to see if keys are mutually comparable.
 * This implementation passes the navigable map test suites.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible

import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A wrapper around {@code TreeMap} that aggressively checks to see if keys are mutually comparable.
 * This implementation passes the navigable map test suites.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible

    for (Entry<K, V> entry : entries) {
      assertFalse("Should not contain entry " + entry, actualContents().contains(entry));
      assertFalse(
          "Should not contain key " + entry.getKey() + " mapped to value " + entry.getValue(),
          equal(getMap().get(entry.getKey()), entry.getValue()));
    }
  }

  private static boolean equal(@Nullable Object a, @Nullable Object b) {

  /**
   * Returns an immutable list containing the given elements, sorted according to their natural
   * order. The sorting algorithm used is stable, so elements that compare as equal will stay in the
   * order in which they appear in the input.
   *
   * <p>If your data has no duplicates, or you wish to deduplicate elements, use {@code
   * ImmutableSortedSet.copyOf(elements)}; if you want a {@code List} you can use its {@code
   * asList()} view.