src/transformers/training_args.py/TrainingArguments/n_gpu
class TrainingArguments:    def n_gpu(self):
        """
        The number of GPUs used by this process.

        Note:
            This will only be greater than one when you have multiple GPUs available but are not using distributed
            training. For distributed training, it will always be 1.
        """
        # Make sure `self._n_gpu` is properly setup.
        _ = self._setup_devices
        return self._n_gpu