&& (upperBound == null || compare(upperBound, o) > 0);
    }

    @Override
    public SortedMap<C, V> subMap(C fromKey, C toKey) {
      checkArgument(rangeContains(checkNotNull(fromKey)) && rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, fromKey, toKey);
    }

    @Override
    public SortedMap<C, V> headMap(C toKey) {
      checkArgument(rangeContains(checkNotNull(toKey)));

      @ParametricNullness K fromKey, @ParametricNullness K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public NavigableMap<K, V> subMap(
      @ParametricNullness K fromKey,
      boolean fromInclusive,
      @ParametricNullness K toKey,
      boolean toInclusive) {
    return delegate().subMap(fromKey, fromInclusive, toKey, toInclusive);
  }

  @Override

      @ParametricNullness K fromKey, @ParametricNullness K toKey) {
    return subMap(fromKey, true, toKey, false);
  }

  @Override
  public NavigableMap<K, V> subMap(
      @ParametricNullness K fromKey,
      boolean fromInclusive,
      @ParametricNullness K toKey,
      boolean toInclusive) {
    return delegate().subMap(fromKey, fromInclusive, toKey, toInclusive);
  }

  @Override

        return ImmutableSortedMap.of();
      }
    }

    @Override
    public NavigableMap<Cut<C>, Range<C>> subMap(
        Cut<C> fromKey, boolean fromInclusive, Cut<C> toKey, boolean toInclusive) {
      return subMap(
          Range.range(
              fromKey, BoundType.forBoolean(fromInclusive),
              toKey, BoundType.forBoolean(toInclusive)));
    }

    @Override

    public SortedMap<K, Collection<V>> subMap(
        @ParametricNullness K fromKey, @ParametricNullness K toKey) {
      return new SortedAsMap(sortedMap().subMap(fromKey, toKey));
    }

    @Override
    public SortedMap<K, Collection<V>> tailMap(@ParametricNullness K fromKey) {
      return new SortedAsMap(sortedMap().tailMap(fromKey));
    }

    @Nullable SortedSet<K> sortedKeySet;

          && (upperBound == null || compare(upperBound, o) > 0);
    }

    @Override
    public SortedMap<C, V> subMap(C fromKey, C toKey) {
      checkArgument(rangeContains(checkNotNull(fromKey)) && rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, fromKey, toKey);
    }

    @Override
    public SortedMap<C, V> headMap(C toKey) {
      checkArgument(rangeContains(checkNotNull(toKey)));

      standardClear();
    }

    @Override
    public boolean isEmpty() {
      return standardIsEmpty();
    }

    @Override
    public SortedMap<K, V> subMap(K fromKey, K toKey) {
      return standardSubMap(fromKey, toKey);
    }

    @Override
    public @Nullable Entry<K, V> lowerEntry(K key) {
      return standardLowerEntry(key);
    }

    @Override

      standardClear();
    }

    @Override
    public boolean isEmpty() {
      return standardIsEmpty();
    }

    @Override
    public SortedMap<K, V> subMap(K fromKey, K toKey) {
      return standardSubMap(fromKey, toKey);
    }

    @Override
    public @Nullable Entry<K, V> lowerEntry(K key) {
      return standardLowerEntry(key);
    }

    @Override

  /**
   * Remove {@code edge} from the set of incoming edges. Returns the former predecessor node.
   *
   * <p>In the undirected case, returns {@code null} if {@code isSelfLoop} is true.
   */
  @CanIgnoreReturnValue
  @Nullable N removeInEdge(E edge, boolean isSelfLoop);

  /** Remove {@code edge} from the set of outgoing edges. Returns the former successor node. */
  @CanIgnoreReturnValue
  N removeOutEdge(E edge);

  /**

      standardClear();
    }

    @Override
    public boolean isEmpty() {
      return standardIsEmpty();
    }

    @Override
    public SortedMap<K, V> subMap(K fromKey, K toKey) {
      return standardSubMap(fromKey, toKey);
    }
  }

  @AndroidIncompatible // test-suite builders
  public static Test suite() {
    TestSuite suite = new TestSuite();