'We can specify that we want to use default preprocessors despite
passing our own ones in the constructor'

def test_use_default_preprocessors_property(self):

    learner = DummyLearnerPP(preprocessors=(Discretize(),))
    learner.use_default_preprocessors = True
    preprocessors = list(learner.active_preprocessors)
    self.assertEqual(len(preprocessors), 2, 'Learner    did    not    properly    insert    custom    preprocessor    into    preprocessor    list')
    self.assertIsInstance(preprocessors[0], Discretize, 'Custom    preprocessor    was    inserted    in    incorrect    order')
    self.assertIsInstance(preprocessors[1], Randomize)
