refactor building accelerator args so it can easily be extended in do…

…wnstream trainers

src/transformers/trainer.py

@@ -4705,7 +4705,7 @@ def _add_sm_patterns_to_gitignore(self) -> None:
             self.repo.git_commit("Add *.sagemaker patterns to .gitignore.")
             self.repo.git_push()
 
-    def create_accelerator_and_postprocess(self):
+    def build_accelerator_args(self):
         grad_acc_kwargs = {}
         if is_accelerate_available("0.28.0") and self.args.accelerator_config.gradient_accumulation_kwargs is not None:
             grad_acc_kwargs = self.args.accelerator_config.gradient_accumulation_kwargs
@@ -4758,7 +4758,10 @@ def create_accelerator_and_postprocess(self):
             args["dataloader_config"] = dataloader_config
         else:
             args.update(accelerator_config)
+        return args
 
+    def create_accelerator_and_postprocess(self):
+        args = self.build_accelerator_args()
         # create accelerator object
         self.accelerator = Accelerator(**args)
         # some Trainer classes need to use `gather` instead of `gather_for_metrics`, thus we store a flag