def test_periodIntersect_whenPartiallyOverlap(self) :
p1 = Period("2013-01-01","2015-03-20")
p2 = Period("2015-01-01","2016-03-20")
self.assertEqual(
p1.intersect(p2).t,
("2015-01-01","2015-03-20"))
def test_periodIntersect_whenDifers(self) :
p1 = Period("2013-01-01","2014-03-20")
p2 = Period("2015-01-01","2016-03-20")
self.assertEqual(
p1.intersect(p2).t,
("2015-01-01","2014-03-20"))
