new_contents: """
      https://leetcode.com/problems/add-two-numbers/
      Add two linked list numbers with different length
      edge cases:
          different length
          
  
      (2 -> 4 -> 3) + (5 -> 6 -> 4) = 7 -> 0 -> 8
      while i in l1 and while  j in l2:
              add i and j
              create a node
              set value to the node(divide by 10)
              keep reminder
  
  
  """
subject: add two numbers initial commit