code: public static <U> Try<U> flatten(final Try<? extends Try<? extends U>> nestedTry) {
      if (nestedTry.isFailure()) {
        return fromError(nestedTry.getError());
      }
  
      return nestedTry.getValue().map(identity());
    }
docs: Flats nested {@link Try} of {@link Try} into flatten one.
  
  @param nestedTry nested try to flatten
  @param <U>       computation type
  @return flatten Try