def test_validate(self):
s = Stack()
s.push(Slice(1, 2, 3))
s.push(Slice(3, 4, 5))
assert s.isValid()
def test_validate(self):
s = Stack()
s.push(Slice(1, 2, 3))
s.push(Slice(3, 4, 5))
assert s.isValid()
