code: func IsNotFound(err error) bool {
  	_, ok := err.(*find.NotFoundError)
  	if ok {
  		return true
  	}
  
  	_, ok = err.(*find.DefaultNotFoundError)
  	if ok {
  		return true
  	}
  
  	return false
  }
docs: // IsNotFound return true if err is NotFoundError or DefaultNotFoundError