addTwoNumbers

class ListNode:
     def __init__(self, data):
         self.data = data
         self.next = None

class Solution:
    def __init__(self):
        self.head = None
        
    def push(self, new_data):
        new_node = ListNode(new_data)
        new_node.next = self.head
        self.head = new_node
    
    def addTwoNumbers(self, l1, l2):
         dummyHead = ListNode(0)
         tail = dummyHead
         carry = 0
         
         
         while l1 is not None or l2 is not None or carry != 0:
                    
                    digit1 = 0 if l1 is None else l1
                    digit2 = 0 if l2 is None else l2
                    sum = digit1 + digit2 + carry        #ERROR HERE with my code and using a driver from google search
                    digit = sum % 10
                    carry = sum // 10

                    new_node = ListNode(digit)#create new node
                    tail.next = new_node#add new node to tail node
                    tail = tail.next#move the pointer to new node
                    
    def printList(self):
        temp = self.head
        while(temp):
            print (temp.data,end=' ')
            temp = temp.next                

    # result = dummyHead.next 
    # dummyHead.next = None
    # return result    

l1 = Solution() #got this wrong in my approach
l2 = Solution() #got this wrong in my approach

l1.push(2)
l1.push(4)
l1.push(7)

l1.push(5)
l1.push(6)
l1.push(4)

result = Solution()
result.addTwoNumbers(l1,l2)
result.printList