class ListNode: def __init__(self, val=0, next=None): self.val = val self.next = next def addTwoNumbers(l1, l2): list1 = [] list2 = [] trav = l1 while trav != None: list1.append(trav.val) trav = trav.next trav = l2 while trav != None: list2.append(trav.val) trav = trav.next print(list1) print(list2) l1 = ListNode() trav = l1 for i in range(4): trav = ListNode() trav.val = i trav = trav.next l2 = ListNode() trav = l2 for i in range(4): trav = ListNode() trav.val = i trav = trav.next addTwoNumbers(l1, l2)