List<String> transform = Lists.transform(listIteratorOnlyList, SOME_FUNCTION);
    assertTrue(
        Iterables.elementsEqual(transform, Lists.transform(randomAccessList, SOME_FUNCTION)));
  }

  private static class ListIterationOnlyList<E> extends ForwardingList<E> {
    private final List<E> realDelegate;

    private ListIterationOnlyList(List<E> realDelegate) {
      this.realDelegate = realDelegate;
    }

  }

  public void testTransform_absent() {
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.identity()));
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.toStringFunction()));
  }

  public void testTransform_presentIdentity() {
    assertEquals(Optional.of("a"), Optional.of("a").transform(Functions.identity()));
  }

  public void testTransform_presentToString() {

    List<String> transform = Lists.transform(listIteratorOnlyList, SOME_FUNCTION);
    assertTrue(
        Iterables.elementsEqual(transform, Lists.transform(randomAccessList, SOME_FUNCTION)));
  }

  private static class ListIterationOnlyList<E> extends ForwardingList<E> {
    private final List<E> realDelegate;

    private ListIterationOnlyList(List<E> realDelegate) {
      this.realDelegate = realDelegate;
    }

        return ImmutableMap.copyOf(sourceMap);
      }
    },
    COPY_OF_ENTRIES {
      @Override
      public Map<Object, Object> create(List<?> keys) {
        return ImmutableMap.copyOf(
            Lists.transform(keys, k -> Maps.immutableEntry(k, "dummy value")));
      }
    },
    BUILDER_PUT_ONE_BY_ONE {
      @Override
      public Map<Object, Object> create(List<?> keys) {

    }
    Set<List<Optional<?>>> cartesianProduct = Sets.cartesianProduct(optionalSets);
    return Iterables.transform(
        cartesianProduct,
        new Function<List<Optional<?>>, List<Object>>() {
          @Override
          public List<Object> apply(List<Optional<?>> objs) {
            return Lists.transform(objs, OPTIONAL_TO_NULLABLE);
          }
        });
  }

    }
    Set<List<Optional<?>>> cartesianProduct = Sets.cartesianProduct(optionalSets);
    return Iterables.transform(
        cartesianProduct,
        new Function<List<Optional<?>>, List<Object>>() {
          @Override
          public List<Object> apply(List<Optional<?>> objs) {
            return Lists.transform(objs, OPTIONAL_TO_NULLABLE);
          }
        });
  }

    assertThat(transformation.inverse().isVertical()).isFalse();
    assertThat(transformation.transform(x1)).isWithin(ALLOWED_ERROR).of(y1);
    assertThat(transformation.transform(x1 + xDelta)).isWithin(ALLOWED_ERROR).of(y1 + yDelta);
    assertThat(transformation.inverse().transform(y1)).isWithin(ALLOWED_ERROR).of(x1);
    assertThat(transformation.inverse().transform(y1 + yDelta))
        .isWithin(ALLOWED_ERROR)
        .of(x1 + xDelta);

  }

  public void testTransform_absent() {
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.identity()));
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.toStringFunction()));
  }

  public void testTransform_presentIdentity() {
    assertEquals(Optional.of("a"), Optional.of("a").transform(Functions.identity()));
  }

  public void testTransform_presentToString() {

                        keys ->
                            path.create(
                                Lists.transform(
                                    keys, key -> Maps.immutableEntry(key, new Object()))),
                        keys ->
                            path.create(
                                Lists.transform(
                                    keys, key -> Maps.immutableEntry(new Object(), key))),

        Entry<String, String> entry = (Entry<String, String>) o;
        multimap.put(entry.getKey(), Ascii.toUpperCase(entry.getValue()));
      }
      return transform(multimap);
    }

    abstract M transform(Multimap<String, String> multimap);

    @SuppressWarnings("unchecked")
    @Override
    public Entry<String, String>[] createArray(int length) {