def METHOD_NAME(self, data_files, *args):
    for fullname in data_files:
        with open(fullname, "r", encoding="utf8") as fr:
            samples = json.load(fr)
            for sample in samples:
                context = sample[0]
                qas = sample[1]
                for qa in qas:
                    question = qa["question"]
                    choice = qa["choice"]
                    answer = qa["answer"]
                    label = str(choice.index(answer))
                    yield {
                        "context": context,
                        "question": question,
                        "choice": choice,
                        "answer": answer,
                        "label": label,
                    }