Many places in tests code use assertEqual(AA, None), the same with True and False and negatives of such comparisons. As comparison to singletons must use `is` operator, appropriate usage is assertIs, assertIsNot, assertIsNone, assertIsNotNone These assertions are provided by the `testtools` package, so this change is not breaking backward compatibility with Python 2.6 Change-Id: I232136ce49afdb8bf78b42221454540471d12c23 Closes-Bug: #1259023