code: func checkResourceExistsFromError(err error) (bool, error) {
  	if err == nil {
  		return true, nil
  	}
  	v, ok := err.(autorest.DetailedError)
  	if ok && v.StatusCode == http.StatusNotFound {
  		return false, nil
  	}
  	return false, v
  }
docs: // checkExistsFromError inspects an error and returns a true if err is nil,
  // false if error is an autorest.Error with StatusCode=404 and will return the
  // error back if error is another status code or another type of error.