Doubly Linked List.py

class Node:
    def __init__(self, value):
        self.value = value
        self.prev = None
        self.next = None

# Feel free to add new properties and methods to the class.


class DoublyLinkedList:
    def __init__(self):
        self.head = None
        self.tail = None

    def setHead(self, node):
        if self.head is None:
            self.head = node
            self.tail = node
            return
        self.insertBefore(self.head, node)

    def setTail(self, node):
        if self.tail is None:
            self.setHead(node)      
            return
        self.insertAfter(self.tail, node)
		
    def insertBefore(self, node, nodeToInsert):
        if nodeToInsert==self.head and nodeToInsert==self.tail:
            return
        self.remove(nodeToInsert)
        nodeToInsert.prev = node.prev
        nodeToInsert.next = node
        if node.prev is None:
            self.head=nodeToInsert
        else:
            node.prev.next = nodeToInsert
        node.next = nodeToInsert
		
		
    def insertAfter(self, node, nodeToInsert):
        if nodeToInsert ==self.head and nodeToInsert == self.tail:
            return
        self.remove(nodeToInsert)
        nodeToInsert.prev = node
        nodeToInsert.next=node.next
        if node.next is None:
            self.tail=nodeToInsert
        else:
            node.next.prev=nodeToInsert
        node.next=nodeToInsert

    def insertAtPosition(self, position, nodeToInsert):
        if position ==1:
            self.setHead(nodeToInsert)
            return
        node =self.head
        currentPosition=1
        while node is not None and currentPosition !=position:
            node=node.next
            currentPosition+=1
        if node is not None:
            self.insertBefore(node, nodeToInsert)
        else:
            self.setTail(nodeToInsert)

    def removeNodesWithValue(self, value):
        node=self.head
        while node is not None:
            nodeToRemove=node
            node=node.next
            if nodeToRemove.value==value:
                self.remove(nodeToRemove)


    def remove(self, node):
        if node==self.head:
            self.head=self.head.next
        if node==self.tail:
            self.tail=self.tail.prev
        self.removeNodeBindings(node)

    def containsNodeWithValue(self, value):
        node=self.head
        while node is not None and node.value !=value:
            node=node.next
        return node is not None
	
    def removeNodeBindings(self, node):
        if node.prev is not None:
            node.prev.next = node.next
        if node.next is not None:
            node.next.prev=node.prev
        node.prev=None
        node.prev=None