code: func (b *Backend) getExpiresIn() int {
  	resultsExpireIn := b.GetConfig().ResultsExpireIn * 1000
  	if resultsExpireIn == 0 {
  		// // expire results after 1 hour by default
  		resultsExpireIn = config.DefaultResultsExpireIn * 1000
  	}
  	return resultsExpireIn
  }
docs: // getExpiresIn returns expiration time