def sumIt(n1, n2, carry):
if (n1 is None) and (n2 is None):
return None
result = Node()
v = carry
if n1 is not None:
v += n1.value
if n2 is not None:
v += n2.value
result.value = v%10
next = sumIt(n1.next, n2.next, v/10)
result.next = next
return result
