BiMap<K, V> bimap = (BiMap<K, V>) map;

    for (Entry<K, V> entry : map.entrySet()) {
      assertEquals(entry.getKey() + "=" + entry.getValue(), entry.toString());
      assertEquals(entry.getKey(), bimap.inverse().get(entry.getValue()));
    }

    assertEquals("{" + JOINER.join(map.entrySet()) + "}", map.toString());
    assertEquals("[" + JOINER.join(map.entrySet()) + "]", map.entrySet().toString());

    BiMap<K, V> bimap = (BiMap<K, V>) map;

    for (Entry<K, V> entry : map.entrySet()) {
      assertEquals(entry.getKey() + "=" + entry.getValue(), entry.toString());
      assertEquals(entry.getKey(), bimap.inverse().get(entry.getValue()));
    }

    assertEquals("{" + JOINER.join(map.entrySet()) + "}", map.toString());
    assertEquals("[" + JOINER.join(map.entrySet()) + "]", map.entrySet().toString());

    return new Builder<K, V>().putAll(entries).build();
  }

  ImmutableBiMap(Map<K, V> delegate) {
    super(delegate);
  }

  public abstract ImmutableBiMap<V, K> inverse();

  @Override
  public ImmutableSet<V> values() {
    return inverse().keySet();
  }

  public final @Nullable V forcePut(K key, V value) {
    throw new UnsupportedOperationException();
  }

    return Collections.unmodifiableSet(((BiMap<E, N>) outEdgeMap).values());
  }

  @Override
  public Set<E> edgesConnecting(N node) {
    return new EdgesConnecting<>(((BiMap<E, N>) outEdgeMap).inverse(), node);
  }

    return Collections.unmodifiableSet(((BiMap<E, N>) outEdgeMap).values());
  }

  @Override
  public Set<E> edgesConnecting(N node) {
    return new EdgesConnecting<>(((BiMap<E, N>) outEdgeMap).inverse(), node);
  }

    System.out.println("hit rate: " + hit / req);
  }

  // for proper distributions later:
  // import JSci.maths.statistics.ProbabilityDistribution;
  // int key = (int) dist.inverse(random.nextDouble());

  public ImmutableCollection<V> values() {
    if (cachedValues != null) {
      return cachedValues;
    }
    return cachedValues = createValues();
  }

  // cached so that this.multimapView().inverse() only computes inverse once
  private transient @Nullable ImmutableSetMultimap<K, V> multimapView;

  public ImmutableSetMultimap<K, V> asMultimap() {
    ImmutableSetMultimap<K, V> result = multimapView;

    return fromLongBits(value);
  }

  /**
   * Returns a {@code UnsignedLong} representing the same value as the specified {@code BigInteger}.
   * This is the inverse operation of {@link #bigIntegerValue()}.
   *
   * @throws IllegalArgumentException if {@code value} is negative or {@code value >= 2^64}
   */
  @CanIgnoreReturnValue
  public static UnsignedLong valueOf(BigInteger value) {

      }
    }
    return current;
  }

  /**
   * Returns the unique least value of type {@code C} that is greater than {@code value}, or {@code
   * null} if none exists. Inverse operation to {@link #previous}.
   *
   * @param value any value of type {@code C}
   * @return the least value greater than {@code value}, or {@code null} if {@code value} is {@code
   *     maxValue()}
   */

      }
    }
    return current;
  }

  /**
   * Returns the unique least value of type {@code C} that is greater than {@code value}, or {@code
   * null} if none exists. Inverse operation to {@link #previous}.
   *
   * @param value any value of type {@code C}
   * @return the least value greater than {@code value}, or {@code null} if {@code value} is {@code
   *     maxValue()}
   */