code: func (m method) FailedRespBodyTypes() (resps []respBody) {
  	for _, resp := range m.RespBodyTypes() {
  		if resp.Code < 200 || resp.Code >= 300 {
  			resps = append(resps, resp)
  		}
  	}
  	return
  }
docs: // FailedRespBodyTypes return all response body that considered a failed response
  // i.e. non 2xx status code