}
  }

  private static boolean equal(@Nullable Object a, @Nullable Object b) {
    return a == b || (a != null && a.equals(b));
  }

  // This one-liner saves us from some ugly casts
  protected Entry<K, V> entry(K key, V value) {
    return Helpers.mapEntry(key, value);
  }

  @Override
  protected void expectContents(Collection<Entry<K, V>> expected) {

    }
  }

  private static boolean equal(@Nullable Object a, @Nullable Object b) {
    return a == b || (a != null && a.equals(b));
  }

  // This one-liner saves us from some ugly casts
  protected Entry<K, V> entry(K key, V value) {
    return Helpers.mapEntry(key, value);
  }

  @Override
  protected void expectContents(Collection<Entry<K, V>> expected) {

    }

    @Override
    public E aboveSamplesGreater() {
      throw new UnsupportedOperationException();
    }
  }

  /*
   * TODO(cpovirk): surely we can find a less ugly solution than a class that accepts 3 parameters,
   * exposes as many getters, does work in the constructor, and has both a superclass and a subclass
   */
  public static class SortedMapSubmapTestMapGenerator<

    }

    @Override
    public E aboveSamplesGreater() {
      throw new UnsupportedOperationException();
    }
  }

  /*
   * TODO(cpovirk): surely we can find a less ugly solution than a class that accepts 3 parameters,
   * exposes as many getters, does work in the constructor, and has both a superclass and a subclass
   */
  public static class SortedMapSubmapTestMapGenerator<

     * handling not just {@code Iterable<S>} instances, but also any {@code
     * Iterable<? extends S>}. However, the need for this comes up so rarely
     * that it doesn't justify making everyone else deal with the very ugly
     * wildcard.
     */
    return new LexicographicalOrdering<S>(this);
  }

  // Regular instance methods

  @Override

    // Ideally, the returned equivalence would support Iterable<? extends T>. However,
    // the need for this is so rare that it's not worth making callers deal with the ugly wildcard.
    return new PairwiseEquivalence<>(this);
  }

  /**
   * Returns a predicate that evaluates to true if and only if the input is equivalent to {@code
   * target} according to this equivalence relation.

    // Ideally, the returned equivalence would support Iterable<? extends T>. However,
    // the need for this is so rare that it's not worth making callers deal with the ugly wildcard.
    return new PairwiseEquivalence<>(this);
  }

  /**
   * Returns a predicate that evaluates to true if and only if the input is equivalent to {@code
   * target} according to this equivalence relation.

    }
  }

  /**
   * Returns the specified comparator if not null; otherwise returns {@code Ordering.natural()}.
   * This method is an abomination of generics; the only purpose of this method is to contain the
   * ugly type-casting in one place.
   */
  @SuppressWarnings("unchecked")
  static <E extends @Nullable Object> Comparator<? super E> orNaturalOrder(
      @CheckForNull Comparator<? super E> comparator) {