@Override
    public NavigableSet<V> headSet(@ParametricNullness V toElement, boolean inclusive) {
      return wrap(getSortedSetDelegate().headSet(toElement, inclusive));
    }

    @Override
    public NavigableSet<V> tailSet(@ParametricNullness V fromElement, boolean inclusive) {
      return wrap(getSortedSetDelegate().tailSet(fromElement, inclusive));
    }
  }

  }

  @Override
  public NavigableMap<K, V> headMap(@ParametricNullness K toKey, boolean inclusive) {
    return delegate().headMap(toKey, inclusive);
  }

  @Override
  public NavigableMap<K, V> tailMap(@ParametricNullness K fromKey, boolean inclusive) {
    return delegate().tailMap(fromKey, inclusive);
  }

  /**
   * A sensible definition of {@link #headMap(Object)} in terms of {@link #headMap(Object,

  }

  @Override
  public NavigableMap<K, V> headMap(@ParametricNullness K toKey, boolean inclusive) {
    return delegate().headMap(toKey, inclusive);
  }

  @Override
  public NavigableMap<K, V> tailMap(@ParametricNullness K fromKey, boolean inclusive) {
    return delegate().tailMap(fromKey, inclusive);
  }

  /**
   * A sensible definition of {@link #headMap(Object)} in terms of {@link #headMap(Object,

      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.NO_BOUND, Bound.EXCLUSIVE));
      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.INCLUSIVE, Bound.NO_BOUND));
      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.INCLUSIVE, Bound.EXCLUSIVE));
    }

    return derivedSuites;
  }

  @Override
  protected SetTestSuiteBuilder<K> createDerivedKeySetSuite(TestSetGenerator<K> keySetGenerator) {

    } else {
      int k = 20;
      return BigInteger.valueOf(LongMath.factorial(k)).multiply(oldSlowFactorial(k, n));
    }
  }

  /** Returns the product of {@code n1} exclusive through {@code n2} inclusive. */
  @SuppressWarnings("UseCorrectAssertInTests") // TODO(b/345814817): Remove or convert assertion.
  private static BigInteger oldSlowFactorial(int n1, int n2) {
    assert n1 <= n2;

      derivedSuites.add(createSubsetSuite(parentBuilder, Bound.NO_BOUND, Bound.EXCLUSIVE));
      derivedSuites.add(createSubsetSuite(parentBuilder, Bound.INCLUSIVE, Bound.NO_BOUND));
      derivedSuites.add(createSubsetSuite(parentBuilder, Bound.INCLUSIVE, Bound.EXCLUSIVE));
    }

    return derivedSuites;
  }

  /**
   * Creates a suite whose set has some elements filtered out of view.
   *

      derivedSuites.add(createSubsetSuite(parentBuilder, Bound.NO_BOUND, Bound.EXCLUSIVE));
      derivedSuites.add(createSubsetSuite(parentBuilder, Bound.INCLUSIVE, Bound.NO_BOUND));
      derivedSuites.add(createSubsetSuite(parentBuilder, Bound.INCLUSIVE, Bound.EXCLUSIVE));
    }

    return derivedSuites;
  }

  /**
   * Creates a suite whose set has some elements filtered out of view.
   *

nationality, personal appearance, race, religion, or sexual identity and
orientation.

## Our Standards

Examples of behavior that contributes to creating a positive environment
include:

* Using welcoming and inclusive language
* Being respectful of differing viewpoints and experiences
* Gracefully accepting constructive criticism
* Focusing on what is best for the community
* Showing empathy towards other community members

      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.NO_BOUND, Bound.EXCLUSIVE));
      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.INCLUSIVE, Bound.NO_BOUND));
      derivedSuites.add(createSubmapSuite(parentBuilder, Bound.INCLUSIVE, Bound.EXCLUSIVE));
    }

    return derivedSuites;
  }

  @Override
  protected SetTestSuiteBuilder<K> createDerivedKeySetSuite(TestSetGenerator<K> keySetGenerator) {

    ImmutableSortedSet<E> set = headSet(e, true);
    return !set.isEmpty() ? set.last() : null;
  }

  public ImmutableSortedSet<E> headSet(E toElement, boolean inclusive) {
    checkNotNull(toElement);
    if (inclusive) {
      E tmp = higher(toElement);
      if (tmp == null) {
        return this;
      }
      toElement = tmp;
    }
    return headSet(toElement);
  }