fix #3116

Former-commit-id: b7256aa33d761280751518c20f29f9b8ea3fb025

src/llmtuner/hparams/parser.py

@@ -120,7 +120,7 @@ def get_train_args(args: Optional[Dict[str, Any]] = None) -> _TRAIN_CLS:
 
     if (
         finetuning_args.stage == "ppo"
-        and training_args.report_to is not None
+        and training_args.report_to
         and training_args.report_to[0] not in ["wandb", "tensorboard"]
     ):
         raise ValueError("PPO only accepts wandb or tensorboard logger.")