def test_collapse(self):
    obj1 = object()
    obj2 = object()
    c = Collection([[obj1], [obj2]])
    self.assertEqual([obj1, obj2], c.collapse().all())
def test_collapse(self):
    obj1 = object()
    obj2 = object()
    c = Collection([[obj1], [obj2]])
    self.assertEqual([obj1, obj2], c.collapse().all())