rotate ll python

# program to rotate 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()

    # rotate a linked list
    # function removes nodes from the beginning and puts them to the end of the linked list;
    def rotate(self, shiftValue):
        current = self.head
        tail = self.head

        # make tail point the last element
        while tail.getNextNode() is not None:
            tail = tail.getNextNode()

        for i in range(shiftValue):
            tail.setLink(current)
            current = current.getNextNode()
            tail = tail.getNextNode()
            tail.setLink(None)


        # let head point to the new head node
        self.head = current
        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
# creating LinkedList
myList = LinkedList()
myList.addToStart(1)
myList.addToEnd(2)
myList.addToEnd(3)
myList.addToEnd(4)
myList.addToEnd(5)
myList.addToEnd(6)
myList.addToEnd(7)
myList.addToEnd(8)
myList.addToEnd(9)
myList.addToEnd(10)
myList.addToEnd(11)

print("Program to rotate linked list elements")
myList.display()


print("\nRotating linked list by 4 places")
myList.rotate(4)
myList.display()