def test_transform(self):
    c = Collection([1, 2, 3, 4])
    c.transform((lambda x: (x + 2)))
    self.assertEqual([3, 4, 5, 6], c.all())
def test_transform(self):
    c = Collection([1, 2, 3, 4])
    c.transform((lambda x: (x + 2)))
    self.assertEqual([3, 4, 5, 6], c.all())