code: func (l *SimpleLRUCache) DeleteAll() {
  	for lru := l.cache.Back(); lru != nil; lru = l.cache.Back() {
  		l.cache.Remove(lru)
  		delete(l.elements, string(lru.Value.(*cacheEntry).key.Hash()))
  		l.size--
  	}
  }
docs: // DeleteAll deletes all elements from the LRU Cache.