follow #4878 fix #4684

Former-commit-id: 4715e5c5b8040b21e5f401f7e969b9fd2757d520

src/llamafactory/hparams/parser.py

@@ -162,9 +162,6 @@ def get_train_args(args: Optional[Dict[str, Any]] = None) -> _TRAIN_CLS:
     # Check arguments
     if finetuning_args.stage != "pt" and data_args.template is None:
         raise ValueError("Please specify which `template` to use.")
-    
-    if finetuning_args.stage == "pt" and data_args.train_last_turn_only:
-        raise ValueError("PT stage does not support `train_last_turn_only`.")
 
     if finetuning_args.stage != "sft" and training_args.predict_with_generate:
         raise ValueError("`predict_with_generate` cannot be set as True except SFT.")