def test_multipleNonOfferItemsAreMultiplesOfSingleItemPrice(self):
    self.assertEqual(checkout('CC'), (checkout('C') * 2))
    self.assertEqual(checkout('DD'), (checkout('D') * 2))
def test_multipleNonOfferItemsAreMultiplesOfSingleItemPrice(self):
    self.assertEqual(checkout('CC'), (checkout('C') * 2))
    self.assertEqual(checkout('DD'), (checkout('D') * 2))