code: func (cache *Cache) pruneInterval() time.Duration {
  	if cache.AccessUpdateInterval > 0 && cache.PruneFactor > 0 {
  		return cache.AccessUpdateInterval * time.Duration(1+cache.PruneFactor)
  	}
  	return 0
  }
docs: // pruneInterval calculates the prune interval. This is a function of the
  // cache's AccessUpdateInterval and PruneFactor.
  //
  // If either AccessUpdateInterval or PruneFactor is <= 0, this will return 0,
  // indicating no prune interval.