src/transformers/trainer.py/Trainer/_move_model_to_device
class Trainer:    def _move_model_to_device(self, model, device):
        model = model.to(device)
        # Moving a model to an XLA device disconnects the tied weights, so we have to retie them.
        if self.args.parallel_mode == ParallelMode.TPU and hasattr(model, "tie_weights"):
            model.tie_weights()