def METHOD_NAME(paths=[]):
    sentences = []
    for sen_path in paths:
        assert os.path.isfile(sen_path), "The {} isn't a valid file.".format(sen_path)
        sen = read_file(sen_path)
        if sen is None:
            logger.info("error in loading file:{}".format(sen_path))
            continue
        sentences.extend(sen)
    return sentences