/**
     * Associates {@code key} with {@code value} in the built map. Duplicate keys are not allowed,
     * and will cause {@link #build} to fail.
     */
    @CanIgnoreReturnValue
    public <T extends B> Builder<B> put(Class<T> key, T value) {
      mapBuilder.put(TypeToken.of(key), value);
      return this;
    }

    /**
     * Associates {@code key} with {@code value} in the built map. Duplicate keys are not allowed,

public class MapMergeTester<K, V> extends AbstractMapTester<K, V> {
  @MapFeature.Require(SUPPORTS_PUT)
  public void testAbsent() {
    assertEquals(
        "Map.merge(absent, value, function) should return value",
        v3(),
        getMap()
            .merge(
                k3(),
                v3(),
                (oldV, newV) -> {
                  throw new AssertionFailedError(

  }

  static final class Item<T> {
    final T value;
    final int groupNumber;
    final int itemNumber;

    Item(T value, int groupNumber, int itemNumber) {
      this.value = value;
      this.groupNumber = groupNumber;
      this.itemNumber = itemNumber;
    }

    @Override
    public String toString() {
      return value + " [group " + (groupNumber + 1) + ", item " + (itemNumber + 1) + ']';

            Lists.transform(keys, k -> Maps.immutableEntry(k, "dummy value")));
      }
    },
    BUILDER_PUT_ONE_BY_ONE {
      @Override
      public Map<Object, Object> create(List<?> keys) {
        ImmutableMap.Builder<Object, Object> builder = ImmutableMap.builder();
        for (Object k : keys) {
          builder.put(k, "dummy value");
        }
        return builder.buildOrThrow();
      }
    },

    for (K key : keySet) {
      V value = map.get(key);
      expectedKeySetHash += key != null ? key.hashCode() : 0;
      assertTrue(map.containsKey(key));
      assertTrue(map.containsValue(value));
      assertTrue(valueCollection.contains(value));
      assertTrue(valueCollection.containsAll(Collections.singleton(value)));
      assertTrue(entrySet.contains(mapEntry(key, value)));

    assertNull(segment.get(key, hash));
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    // don't see absent values now that count > 0
    assertNull(segment.get(new Object(), hash));

    // null key

    assertNull(segment.get(key, hash));
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));
    // don't see absent values now that count > 0
    assertNull(segment.get(new Object(), hash));

    // null key

   * that all the values with indexes in the range [{@code from}, {@code required}) are less than or
   * equal to the value with index {@code required}, and all the values with indexes in the range
   * ({@code required}, {@code to}] are greater than or equal to that value. Therefore, the value at
   * {@code required} is the value which would appear at that index in the sorted dataset.
   */

  }

  /** Returns the associated value type. */
  @GwtIncompatible
  public Class<V> valueType() {
    return valueTypeOrObjectUnderJ2cl;
  }

  @Override
  K checkKey(K key) {
    return checkNotNull(key);
  }

  @Override
  V checkValue(V value) {
    return checkNotNull(value);
  }

  /**

    return adjacentNodeValues.remove(node);
  }

  @Override
  public void addPredecessor(N node, V value) {
    @SuppressWarnings("unused")
    V unused = addSuccessor(node, value);
  }

  @Override
  @CheckForNull
  public V addSuccessor(N node, V value) {
    return adjacentNodeValues.put(node, value);
  }