def test_iter(self):
        prio_set_list = event._PrioritizedSetList()
        objs = [(i,) for i in range(5)]
        for i, obj in enumerate(objs):
            prio_set_list.add(-i, obj)

        for i, set_ in enumerate(prio_set_list):
            assert set_ == (-i, {objs[i]})
def deadline_for_course(cls, course_key):
        """
        Retrieve the verification deadline for a particular course.

        Arguments:
            course_key (CourseKey): The identifier for the course.

        Returns:
            datetime or None

        """
        try:
            deadline = cls.objects.get(course_key=course_key)
            return deadline.deadline
        except cls.DoesNotExist:
            return None