def METHOD_NAME(self, squad_train_examples, squad_preprocessor):
    train_examples, train_features = squad_preprocessor.process_train(squad_train_examples)
    assert isinstance(train_examples, Dataset)
    assert isinstance(train_features, Dataset)
    for example in train_examples:
        assert min(example['target']['start_positions']) >= -1
        assert min(example['target']['end_positions']) >= -1
        assert min(example['target']['passage_indices']) >= -1