def test_and(self):
frames = [Timeframe(1, 4), Timeframe(5, 7), Timeframe(3, 6)]
assert Timeframe.union(frames) == Timeframe(1, 7)
def test_or(self):
frames = [Timeframe(2, 4), Timeframe(1, 4), Timeframe(5, 7),
Timeframe(3, 6)]
assert Timeframe.intersection(frames) is None
frames = [Timeframe(1, 5), Timeframe(5, 7), Timeframe(3, 6)]
assert Timeframe.intersection(frames) == Timeframe(5, 5)
