Consider a class like a HashedLinkedList. This is a linked list which allows direct access to nodes using dictionary look up. It is generally implemented with a

Consider a class like a HashedLinkedList. This is a linked list which allows direct access to nodes using dictionary look up. It is generally implemented with a LinkedList and Dictionary internally. The expectation is that all elements in the dictionary are in the linked list. Any deviation from this implementation detail will cause invalid state. Making the list or the dictionary public opens you up to situations where consumers of the code modify either datastore independently and corrupt the consistency of the class.