docs: public static <T1, T2, R> Optional<R> getOptionalIfExist(
              Optional<T1> firstOptional, Optional<T2> secondOptional,
              BiFunction<T1, T2, R> returnBuilderFunction) {
          return firstOptional.flatMap(t1 -> secondOptional
                  .map(t2 -> returnBuilderFunction.apply(t1, t2)));
      }