src/transformers/integrations.py/NeptuneCallback/on_init_end
class NeptuneCallback:    def on_init_end(self, args, state, control, **kwargs):
        self._volatile_checkpoints_dir = None
        if self._log_checkpoints and (args.overwrite_output_dir or args.save_total_limit is not None):
            self._volatile_checkpoints_dir = tempfile.TemporaryDirectory().name

        if self._log_checkpoints == "best" and not args.load_best_model_at_end:
            raise ValueError("To save the best model checkpoint, the load_best_model_at_end argument must be enabled.")