As explained earlier, at each level within the cache directory, the actual cache is stored as a linked list object. you will use the cache list() class to implement this linked list. each cache has a maximum size of 200 ( note that this does not mean there can be a maximum of 200 items in the cache. it means that the sum of the sizes of all content objects in a cache cannot exceed 200). do not change this value. there are 5 functions you must implement yourself.