def METHOD_NAME(self):
    # Registry is a singleton. Make sure multiple Python 
    # instances can be held.
    instances = []
    for i in range(10):
        instances.append(OCIO.BuiltinTransformRegistry())
    # Other instances should still function after deleting one. The 
    # underlying C++ object is not deleted.
    instance_0 = instances.pop(0)
    self.assertEqual(len(instances), 9)
    del instance_0
    # Variable is no longer defined
    with self.assertRaises(NameError):
        len(instance_0)
    # Test underlying C++ reference validity by accessing registry 
    # data for each instance.
    for instance in instances:
        self.assertGreaterEqual(len(instance), 1)
        self.assertEqual(len(instance), len(self.REGISTRY))