allow non-packing pretraining

Former-commit-id: 3fee5cc5a3db9ce874ad90f2500ec092d904bd4e

src/llmtuner/train/rm/trainer.py

@@ -1,6 +1,6 @@
 import json
 import os
-from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Union
+from typing import TYPE_CHECKING, Dict, List, Tuple, Union
 
 import torch
 from transformers import Trainer
@@ -26,7 +26,7 @@ class PairwiseTrainer(Trainer):
         self.can_return_loss = True  # override property to return eval_loss
 
     def compute_loss(
-        self, model: "PreTrainedModel", inputs: Dict[str, torch.Tensor], return_outputs: Optional[bool] = False
+        self, model: "PreTrainedModel", inputs: Dict[str, torch.Tensor], return_outputs: bool = False
     ) -> Union[torch.Tensor, Tuple[torch.Tensor, List[torch.Tensor]]]:
         r"""
         Computes pairwise loss. The first n examples are chosen and the last n examples are rejected.