def test_sum__not_reversed_plus_carry():
left = LinkedList([6, 1, 9])
right = LinkedList([9, 9, 5])
assert list(sum(left, right, reverse=False).values) == [1, 6, 1, 4]
def test_sum__reverse_nothing():
left = LinkedList([])
right = LinkedList([])
assert list(sum(left, right).values) == []
def test_sum__not_reversed_example():
left = LinkedList([6, 1, 7])
right = LinkedList([2, 9, 5])
assert list(sum(left, right, reverse=False).values) == [9, 1, 2]
def test_sum__not_reversed_zero():
left = LinkedList([0])
right = LinkedList([0])
assert list(sum(left, right, reverse=False).values) == [0]
def test_sum__reverse_plus_carry():
left = LinkedList([9, 1, 6])
right = LinkedList([5, 9, 9])
assert list(sum(left, right).values) == [4, 1, 6, 1]
def test_sum__reverse_example():
left = LinkedList([7, 1, 6])
right = LinkedList([5, 9, 2])
assert list(sum(left, right).values) == [2, 1, 9]
def test_sum__reverse_zero():
left = LinkedList([0])
right = LinkedList([0])
assert list(sum(left, right).values) == [0]