return delegate().forcePut(key, value);
      }
    }

    @Override
    public BiMap<V, K> inverse() {
      synchronized (mutex) {
        if (inverse == null) {
          inverse = new SynchronizedBiMap<>(delegate().inverse(), mutex, this);
        }
        return inverse;
      }
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

        return delegate().forcePut(key, value);
      }
    }

    @Override
    public BiMap<V, K> inverse() {
      synchronized (mutex) {
        if (inverse == null) {
          inverse = new SynchronizedBiMap<>(delegate().inverse(), mutex, this);
        }
        return inverse;
      }
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

    /* No aliasing on inverse operations. */
    assertThat(unmod.inverse()).isSameInstanceAs(unmod.inverse());
    assertThat(unmod.inverse().inverse()).isSameInstanceAs(unmod);

    /* Unmodifiable is a view. */
    mod.put(4, "four");
    assertEquals(true, unmod.get(4).equals("four"));
    assertEquals(true, unmod.inverse().get("four").equals(4));

k{display:inline-block;height:2em;line-height:2em;position:relative;vertical-align:middle;width:2.5em}.fa-stack-1x,.fa-stack-2x{left:0;position:absolute;text-align:center;width:100%}.fa-stack-1x{line-height:inherit}.fa-stack-2x{font-size:2em}.fa-inverse{color:#fff}.fa-500px:before{content:"\f26e"}.fa-accessible-icon:before{content:"\f368"}.fa-accusoft:before{content:"\f369"}.fa-acquisitions-incorporated:before{content:"\f6af"}.fa-ad:before{content:"\f641"}.fa-address-book:before{content:"\f2b9"}...

k{display:inline-block;height:2em;line-height:2em;position:relative;vertical-align:middle;width:2.5em}.fa-stack-1x,.fa-stack-2x{left:0;position:absolute;text-align:center;width:100%}.fa-stack-1x{line-height:inherit}.fa-stack-2x{font-size:2em}.fa-inverse{color:#fff}.fa-500px:before{content:"\f26e"}.fa-accessible-icon:before{content:"\f368"}.fa-accusoft:before{content:"\f369"}.fa-acquisitions-incorporated:before{content:"\f6af"}.fa-ad:before{content:"\f641"}.fa-address-book:before{content:"\f2b9"}...

		}
	}
}

func tenRunes(r rune) string {
	runes := make([]rune, 10)
	for i := range runes {
		runes[i] = r
	}
	return string(runes)
}

// User-defined self-inverse mapping function
func rot13(r rune) rune {
	const step = 13
	if r >= 'a' && r <= 'z' {
		return ((r - 'a' + step) % 26) + 'a'
	}
	if r >= 'A' && r <= 'Z' {
		return ((r - 'A' + step) % 26) + 'A'
	}

   * Copies each key-value mapping in {@code source} into {@code dest}, with its key and value
   * reversed.
   *
   * <p>If {@code source} is an {@link ImmutableMultimap}, consider using {@link
   * ImmutableMultimap#inverse} instead.
   *
   * @param source any multimap
   * @param dest the multimap to copy into; usually empty
   * @return {@code dest}
   */
  @CanIgnoreReturnValue

   * Copies each key-value mapping in {@code source} into {@code dest}, with its key and value
   * reversed.
   *
   * <p>If {@code source} is an {@link ImmutableMultimap}, consider using {@link
   * ImmutableMultimap#inverse} instead.
   *
   * @param source any multimap
   * @param dest the multimap to copy into; usually empty
   * @return {@code dest}
   */
  @CanIgnoreReturnValue

  }

  /**
   * Returns a builder that creates immutable sorted maps whose keys are ordered by the reverse of
   * their natural ordering.
   */
  public static <K extends Comparable<?>, V> Builder<K, V> reverseOrder() {
    return new Builder<>(Ordering.<K>natural().reverse());
  }

  /**
   * A builder for creating immutable sorted map instances, especially {@code public static final}

  }

  /**
   * Returns a builder that creates immutable sorted maps whose keys are ordered by the reverse of
   * their natural ordering.
   */
  public static <K extends Comparable<?>, V> Builder<K, V> reverseOrder() {
    return new Builder<>(Ordering.<K>natural().reverse());
  }

  /**
   * A builder for creating immutable sorted map instances, especially {@code public static final}