code: ResponseWrapper clear(Response response) {
          if (response.getCode() == 200 || response.getCode() == 201) {
              String json = response.getBody();
              try {
                  Gson gson = new GsonBuilder().
                          registerTypeAdapter(JsonElement.class, new JsonElementDeserializer()).
                          create();
                  ResponseWrapper wrapper = gson.fromJson(json, ResponseWrapper.class);
                  if (wrapper == null) {
                      throw new JumblrException(response);
                  }
                  wrapper.setClient(client);
                  return wrapper;
              } catch (JsonSyntaxException ex) {
                  throw new JumblrException(response);
              }
          } else {
              throw new JumblrException(response);
          }
      }
docs: /* package-visible for testing