code: def test_download(self):
      dataset_names = ["pku", "cityu", "as", "msra"]
      for dataset_name in dataset_names:
          data_bundle = CWSLoader(dataset_name=dataset_name).load()
          print(data_bundle)
  
imports: import pytest
  import os
  from fastNLP.io.loader import CWSLoader
label_desc: Use image node_id 1 for calling the TestCWSLoader obj's underlying member method code with example usage: obj.test_download() without return types