}

  @Override
  public @Nullable Entry<K, V> floorEntry(@ParametricNullness K key) {
    return delegate().floorEntry(key);
  }

  /**
   * A sensible definition of {@link #floorEntry} in terms of the {@code lastEntry()} of {@link
   * #headMap(Object, boolean)}. If you override {@code headMap}, you may wish to override {@code
   * floorEntry} to forward to this implementation.
   */

  }

  @Override
  public @Nullable Entry<K, V> floorEntry(@ParametricNullness K key) {
    return delegate().floorEntry(key);
  }

  /**
   * A sensible definition of {@link #floorEntry} in terms of the {@code lastEntry()} of {@link
   * #headMap(Object, boolean)}. If you override {@code headMap}, you may wish to override {@code
   * floorEntry} to forward to this implementation.
   */

    Entry<Cut<C>, Range<C>> floorEntry = rangesByLowerBound.floorEntry(range.lowerBound);
    return floorEntry != null && floorEntry.getValue().encloses(range);
  }

  private @Nullable Range<C> rangeEnclosing(Range<C> range) {
    checkNotNull(range);
    Entry<Cut<C>, Range<C>> floorEntry = rangesByLowerBound.floorEntry(range.lowerBound);
    return (floorEntry != null && floorEntry.getValue().encloses(range))

      assertTrue(Thread.holdsLock(mutex));
      return delegate().firstEntry();
    }

    @Override
    public @Nullable Entry<K, V> floorEntry(K key) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate().floorEntry(key);
    }

    @Override
    public @Nullable K floorKey(K key) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate().floorKey(key);
    }

    public @Nullable K lowerKey(@ParametricNullness K key) {
      return sortedMap().lowerKey(key);
    }

    @Override
    public @Nullable Entry<K, Collection<V>> floorEntry(@ParametricNullness K key) {
      Entry<K, Collection<V>> entry = sortedMap().floorEntry(key);
      return (entry == null) ? null : wrapEntry(entry);
    }

    @Override
    public @Nullable K floorKey(@ParametricNullness K key) {

    public @Nullable K lowerKey(@ParametricNullness K key) {
      return sortedMap().lowerKey(key);
    }

    @Override
    public @Nullable Entry<K, Collection<V>> floorEntry(@ParametricNullness K key) {
      Entry<K, Collection<V>> entry = sortedMap().floorEntry(key);
      return (entry == null) ? null : wrapEntry(entry);
    }

    @Override
    public @Nullable K floorKey(@ParametricNullness K key) {

    return (entry == null) ? null : entry.getValue();
  }

  @Override
  public @Nullable Entry<Range<K>, V> getEntry(K key) {
    Entry<Cut<K>, RangeMapEntry<K, V>> mapEntry =
        entriesByLowerBound.floorEntry(Cut.belowValue(key));
    if (mapEntry != null && mapEntry.getValue().contains(key)) {
      return mapEntry.getValue();
    } else {
      return null;
    }
  }

  @Override

    for (K key : keysToTest) {
      assertEquals(expected.lowerEntry(key), navigableMap.lowerEntry(key));
      assertEquals(expected.floorEntry(key), navigableMap.floorEntry(key));
      assertEquals(expected.ceilingEntry(key), navigableMap.ceilingEntry(key));
      assertEquals(expected.higherEntry(key), navigableMap.higherEntry(key));