add one ll python

# program to add one to a number represented by Linked List

class LinkedList:
    def __init__(self):
        self.head = None

    # returns True is LinkedList is Empty
    def isEmpty(self):
        if self.head is None:
            return True
        else:
            return False

    # method adds elements to the left of the Linked List
    def addToStart(self, data):
        # create a temporary node
        tempNode = Node(data)
        tempNode.setLink(self.head)
        self.head = tempNode
        del tempNode

    # method adds elements to the right of the Linked List
    def addToEnd(self, data):
        start = self.head
        tempNode = Node(data)
        while start.getNextNode():
            start = start.getNextNode()
        start.setLink(tempNode)
        del tempNode
        return True

    # method displays Linked List
    def display(self):
        start = self.head
        if start is None:
            print("Empty List!!!")
            return False

        while start:
            print(str(start.getData()), end=" ")
            start = start.link
            if start:
                print("-->", end=" ")
        print()

    # method reverses the LinkedList
    def reverse(self):
        start = self.head
        tempNode = None
        previousNode = None

        while start:
            tempNode = start.getNextNode()
            start.setLink(previousNode)
            previousNode = start
            start = tempNode

        self.head = previousNode
        return True

    def addOne(self):
        self.reverse()
        self.addingOneUtil()
        self.reverse()

    # adding one to linked list
    def addingOneUtil(self):
        carry = 1
        Sum = 0

        start = self.head
        while start is not None and carry != 0:
            Sum = start.getData() + carry
            start.updateData(Sum % 10)
            carry = int(Sum / 10)
            start = start.getNextNode()

        if carry != 0:
            self.addToEnd(carry)

        return


# node class
class Node:
    # default value of data and link is none if no data is passed
    def __init__(self, data=None, link=None):
        self.data = data
        self.link = link

    # method to update the data feild of Node
    def updateData(self, data):
        self.data = data

    # method to set Link feild the Node
    def setLink(self, node):
        self.link = node

    # method returns data feild of the Node
    def getData(self):
        return self.data

    # method returns address of the next Node
    def getNextNode(self):
        return self.link


# main method
print("Program to add one to a number represented by Linked List")
# creating LinkedList
myList = LinkedList()
myList.addToStart(9)
myList.addToEnd(9)
myList.addToEnd(9)
myList.addToEnd(9)
myList.addToEnd(9)
myList.addToEnd(9)
myList.addToEnd(9)
myList.addToEnd(9)
myList.addToEnd(9)
print("The number is : ")
myList.display()
print("The number after adding one is : ")
myList.addOne()
myList.display()