docs: public Tag create(String name) {
          String url = WxEndpoint.get("url.tag.create");
          TagWrapper tag = new TagWrapper(name);
          String json = JsonMapper.nonEmptyMapper().toJson(tag);
          logger.debug("create tag: {}", json);
          String response = wxClient.post(url, json);
          TagWrapper wrapper = JsonMapper.defaultMapper().fromJson(response, TagWrapper.class);
          return wrapper.getTag();
      }