def process(self, data_batch, data_samples) -> None:
        """transfer tensors in predictions to CPU."""
        for sample in data_samples:
            question_id = sample['question_id']
            pred_answer = sample['pred_answer']

            result = {
                'question_id': int(question_id),
                'answer': pred_answer,
            }

            self.results.append(result)
transfer tensors in predictions to CPU.
mmpretrain/evaluation/metrics/vqa.py