code: def test_wrap_gpu_id(self) -> None:
      assert os.environ["CUDA_VISIBLE_DEVICES"] == "0"
      bst = load_pickle(model_path)
      config = bst.save_config()
      config = json.loads(config)
      assert config["learner"]["generic_param"]["device"] == "cuda:0"
  
      x, y = build_dataset()
      test_x = xgb.DMatrix(x)
      res = bst.predict(test_x)
      assert len(res) == 10
  
file_path: xgboost/tests/python-gpu/load_pickle.py
imports: import json
  import os
  import numpy
  import pytest
  from test_gpu_pickling import build_dataset, load_pickle, model_path
  import xgboost
  from xgboost import testing
label_desc: Use image node_id 4 for calling the TestLoadPickle obj's underlying member method code with example usage: obj.test_wrap_gpu_id() without return types