alter rewards data type

Former-commit-id: 3eb7eb2d37525da50fe401ab7c59532e6e1ef984

src/utils/data_collator.py

@@ -2,7 +2,7 @@ import torch
 
 from typing import Dict, Optional, Sequence, Union
 
-from transformers import DataCollatorWithPadding
+from transformers import DataCollatorWithPadding, BatchEncoding
 from transformers.modeling_utils import PreTrainedModel
 from transformers.tokenization_utils import PreTrainedTokenizer
 
@@ -34,7 +34,7 @@ class DynamicDataCollatorWithPadding(DataCollatorWithPadding):
         attention_mask = attention_mask.bool()
         return attention_mask
 
-    def __call__(self, features: Sequence[Dict[str, Union[torch.Tensor, Sequence[int]]]]) -> Dict[str, torch.Tensor]:
+    def __call__(self, features: Sequence[Dict[str, Union[torch.Tensor, Sequence[int]]]]) -> BatchEncoding:
         r"""
         Pads batched data to the longest sequence in the batch.
 
@@ -64,4 +64,4 @@ class DynamicDataCollatorWithPadding(DataCollatorWithPadding):
         batch["input_ids"] = input_ids
         batch["attention_mask"] = self.get_attention_masks(input_ids, device=input_ids.device)
 
-        return batch
+        return BatchEncoding(batch)