*/

  @CheckForNull
  private B unsafeDoForward(@CheckForNull A a) {
    return doForward(uncheckedCastNullableTToT(a));
  }

  @CheckForNull
  private A unsafeDoBackward(@CheckForNull B b) {
    return doBackward(uncheckedCastNullableTToT(b));
  }

  /**
   * Returns an iterable that applies {@code convert} to each element of {@code fromIterable}. The

   */

  @CheckForNull
  private B unsafeDoForward(@CheckForNull A a) {
    return doForward(uncheckedCastNullableTToT(a));
  }

  @CheckForNull
  private A unsafeDoBackward(@CheckForNull B b) {
    return doBackward(uncheckedCastNullableTToT(b));
  }

  /**
   * Returns an iterable that applies {@code convert} to each element of {@code fromIterable}. The