code: public OptionalThing<String> analyzeRestfulHttpMethod(Method executeMethod) {
          final String extracted = extractRestfulHttpMethod(executeMethod);
          assertResfulHttpMethodIfExists(executeMethod, extracted);
          return OptionalThing.ofNullable(extracted, () -> {
              throw new IllegalStateException("Not found RESTful HTTP method: " + toSimpleMethodExp(executeMethod));
          });
      }
docs: =======