code: public static OptionalThing<Classification> findByCode(Class<?> cdefType, Object code) {
          assertArgumentNotNull("cdefType", cdefType);
          assertArgumentNotNull("code", code);
  
          // #hope switch to nativeFindByCode() in future (can be over DBFlute-1.1.1) by jflute
          final Object result = nativeCodeOf(cdefType, code);
          if (result == null) {
              return OptionalThing.empty();
          }
          if (result instanceof OptionalThing<?>) { // handling for future
              @SuppressWarnings("unchecked")
              final OptionalThing<Classification> cast = (OptionalThing<Classification>) result;
              return cast;
          } else if (result instanceof Optional<?>) {
              @SuppressWarnings("unchecked")
              final Optional<Classification> cast = (Optional<Classification>) result;
              return OptionalThing.ofNullable(cast.orElse(null), () -> {
                  throw new IllegalStateException("Not found the classification code: " + cdefType.getName() + "@" + code);
              });
          } else {
              return OptionalThing.of((Classification) result);
          }
      }
docs: ============