add$($key$,$ value$)$: Adds a new key$-$value pair to the linked dictionary. If the key already exists, the corresponding value should be updated.

get$($key$)$: Returns the value associated with the given key, or None if the key does not exist.

delete$($key$)$: Deletes the key$-$value pair with the given key from the linked dictionary.

You should implement the linked dictionary using the class LinkedDict.

The linked dictionary should store its elements in a linked list.

Implement the linked list using a separate class Node.

Do not use any built$-$in data structures in Python, such as dictionaries, lists, or set