src/transformers/trainer_utils.py/EvalPrediction/__getitem__
class EvalPrediction:    def __getitem__(self, idx):
        if idx < 0 or idx > 2:
            raise IndexError("tuple index out of range")
        if idx == 2 and self.inputs is None:
            raise IndexError("tuple index out of range")
        if idx == 0:
            return self.predictions
        elif idx == 1:
            return self.label_ids
        elif idx == 2:
            return self.inputs