code: func (l *LFUNoTS) remove(ci *cacheItem, position *list.Element) {
  	entry := position.Value.(*entry).listEntry
  	delete(entry, ci)
  	if len(entry) == 0 {
  		l.frequencyList.Remove(position)
  	}
  }
docs: // remove removes the cache item from the cache list
  // after deleting key from the list, if its linked list has no any item no longer
  // then that linked list elemnet will be removed from the list too