def test_order(self):
        assert (event.Priority.PRE_CORE
                > event.Priority.CORE
                > event.Priority.POST_CORE
                > event.Priority.PRE_DEFAULT
                > event.Priority.DEFAULT
                > event.Priority.POST_DEFAULT)
def _get(delta, start):
            p = start
            while delta:
                p = p.next
                delta -= 1
            return p.val