code: public String handleCallBack(HttpMessage msg)  throws ApiException {
  		throw new ApiException (ApiException.Type.URL_NOT_FOUND, msg.getRequestHeader().getURI().toString());
  	}
docs: Override if handling callbacks
  @param msg the HTTP message containing the API request and response
  @return the API response (set in the HTTP response body)
  @throws ApiException if an error occurred while handling the API callback