code: func (s *IdentityService) AddUserLoginAttempt(user string, attempt services.LoginAttempt, ttl time.Duration) error {
  	if err := attempt.Check(); err != nil {
  		return trace.Wrap(err)
  	}
  	value, err := json.Marshal(attempt)
  	if err != nil {
  		return trace.Wrap(err)
  	}
  	item := backend.Item{
  		Key:     backend.Key(webPrefix, usersPrefix, user, attemptsPrefix, uuid.New()),
  		Value:   value,
  		Expires: backend.Expiry(s.Clock(), ttl),
  	}
  	_, err = s.Put(context.TODO(), item)
  	return trace.Wrap(err)
  }
docs: // AddUserLoginAttempt logs user login attempt