def METHOD_NAME(self) -> List[Instance]:
    target_path: str = os.path.join(self.output_path, "data")
    instances: List[Instance] = []
    url: str = f'{"https://ai.stanford.edu/~amaas/data/sentiment/aclImdb_v1.tar.gz"}'
    ensure_file_downloaded(source_url=url, target_path=target_path, unpack=True)
    contrast_map = self.get_contrast_map(target_path, "test")
    contrast_map.update(self.get_contrast_map(target_path, "dev"))
    for split in [TRAIN_SPLIT, VALID_SPLIT]:
        instances.extend(self.get_split_instances(target_path, split, contrast_map))
    return instances