doubly linked list

1# Initialise the Node
2class Node:
3    def __init__(self, data):
4        self.item = data
5        self.next = None
6        self.prev = None
7# Class for doubly Linked List
8class doublyLinkedList:
9    def __init__(self):
10        self.start_node = None
11    # Insert Element to Empty list
12    def InsertToEmptyList(self, data):
13        if self.start_node is None:
14            new_node = Node(data)
15            self.start_node = new_node
16        else:
17            print("The list is empty")
18    # Insert element at the end
19    def InsertToEnd(self, data):
20        # Check if the list is empty
21        if self.start_node is None:
22            new_node = Node(data)
23            self.start_node = new_node
24            return
25        n = self.start_node
26        # Iterate till the next reaches NULL
27        while n.next is not None:
28            n = n.next
29        new_node = Node(data)
30        n.next = new_node
31        new_node.prev = n
32    # Delete the elements from the start
33    def DeleteAtStart(self):
34        if self.start_node is None:
35            print("The Linked list is empty, no element to delete")
36            return 
37        if self.start_node.next is None:
38            self.start_node = None
39            return
40        self.start_node = self.start_node.next
41        self.start_prev = None;
42    # Delete the elements from the end
43    def delete_at_end(self):
44        # Check if the List is empty
45        if self.start_node is None:
46            print("The Linked list is empty, no element to delete")
47            return 
48        if self.start_node.next is None:
49            self.start_node = None
50            return
51        n = self.start_node
52        while n.next is not None:
53            n = n.next
54        n.prev.next = None
55    # Traversing and Displaying each element of the list
56    def Display(self):
57        if self.start_node is None:
58            print("The list is empty")
59            return
60        else:
61            n = self.start_node
62            while n is not None:
63                print("Element is: ", n.item)
64                n = n.next
65        print("\n")
66# Create a new Doubly Linked List
67NewDoublyLinkedList = doublyLinkedList()
68# Insert the element to empty list
69NewDoublyLinkedList.InsertToEmptyList(10)
70# Insert the element at the end
71NewDoublyLinkedList.InsertToEnd(20)
72NewDoublyLinkedList.InsertToEnd(30)
73NewDoublyLinkedList.InsertToEnd(40)
74NewDoublyLinkedList.InsertToEnd(50)
75NewDoublyLinkedList.InsertToEnd(60)
76# Display Data
77NewDoublyLinkedList.Display()
78# Delete elements from start
79NewDoublyLinkedList.DeleteAtStart()
80# Delete elements from end
81NewDoublyLinkedList.DeleteAtStart()
82# Display Data
83NewDoublyLinkedList.Display()
84