linked structures deletions but it does eliminate the constant time direct element access available with the array and python list thusit' not suitable for every data storage problem there are several varieties of linked lists the singly linked list is linear structure in which traversals start at the front and progressone element at timeto the end other variations include the circularly linkedthe doubly linkedand the circularly doubly linked lists introduction suppose we have basic class containing single data fieldclass listnode def __init__selfdata self data data we can create several instances of this classeach storing data of our choosing in the following examplewe create three instanceseach storing an integer valuea listnode listnode listnode the result of which is the creation of three variables and three objects nowsuppose we add second data field to the listnode classclass listnode def __init__selfdata self data data self next none the three objects from the previous example would now have second data field initialized with null referenceas illustrated in the followinga