def test_put(self):
    c = Collection([1, 2, 4])
    c.put(2, 3)
    self.assertEqual([1, 2, 3], c.all())
def test_put(self):
    c = Collection([1, 2, 4])
    c.put(2, 3)
    self.assertEqual([1, 2, 3], c.all())