assertThat(transformation.inverse().inverse()).isSameInstanceAs(transformation);
  }

  /**
   * Asserts that {@code transformation} behaves as expected for {@link
   * LinearTransformation#forNaN}.
   */
  static void assertLinearTransformationNaN(LinearTransformation transformation) {
    assertThat(transformation.isHorizontal()).isFalse();

   * vertical transformation (i.e. when {@link #isVertical()} is true).
   */
  public abstract double transform(double x);

  /**
   * Returns the inverse linear transformation. The inverse of a horizontal transformation is a
   * vertical transformation, and vice versa. The inverse of the {@link #forNaN} transformation is

  @J2ktIncompatible
  @GwtIncompatible // suite
  public static Test suite() {
    TestSuite suite = new TestSuite();

    // Not testing rowKeySet() or columnKeySet() of Table.transformValues()
    // since the transformation doesn't affect the row and column key sets.

    suite.addTest(
        SetTestSuiteBuilder.using(
                new TestStringSetGenerator() {
                  @Override

   *     the returned future.
   * @param executor Executor to run the function in.
   * @return A future that holds result of the transformation.
   * @since 9.0 (in 2.0 as {@code compose})
   */
  public static <I extends @Nullable Object, O extends @Nullable Object>
      ListenableFuture<O> transform(

  }

  /**
   * Returns a view of a multimap whose values are derived from the original multimap's entries. In
   * contrast to {@link #transformValues}, this method's entry-transformation logic may depend on
   * the key as well as the value.
   *
   * <p>All other properties of the transformed multimap, such as iteration order, are left intact.
   * For example, the code:
   *

            ClosingFunction<? super V, U> transformation, @ParametricNullness V input)
            throws Exception {
      // TODO(dpb): Consider ways to defer closing without creating a separate CloseableList.
      CloseableList newCloseables = new CloseableList();
      try {
        return immediateFuture(transformation.apply(newCloseables.closer, input));
      } finally {

    return new TransformedEntriesNavigableMap<>(fromMap, transformer);
  }

  /**
   * A transformation of the value of a key-value pair, using both key and value as inputs. To apply
   * the transformation to a map, use {@link Maps#transformEntries(Map, EntryTransformer)}.
   *
   * @param <K> the key type of the input and output entries

  /**
   * UTF-8: eight-bit UCS Transformation Format.
   *
   * <p><b>Java 7+ users:</b> this constant should be treated as deprecated; use {@link
   * java.nio.charset.StandardCharsets#UTF_8} instead.
   *
   */
  public static final Charset UTF_8 = Charset.forName("UTF-8");

  /**
   * UTF-16BE: sixteen-bit UCS Transformation Format, big-endian byte order.
   *

        ensurePositive(xSumOfSquaresOfDeltas * ySumOfSquaresOfDeltas);
    return ensureInUnitRange(sumOfProductsOfDeltas / Math.sqrt(productOfSumsOfSquaresOfDeltas));
  }

  /**
   * Returns a linear transformation giving the best fit to the data according to <a
   * href="http://mathworld.wolfram.com/LeastSquaresFitting.html">Ordinary Least Squares linear