code: def test_process_from_file_proc(self):
      dataset_names = ["msra", "cityu", "as", "pku"]
      for dataset_name in dataset_names:
          data_bundle = CWSPipe(
              bigrams=True, trigrams=True, num_proc=2
          ).process_from_file(f"data_for_tests/io/cws_{dataset_name}")
          print(data_bundle)
  
file_path: fastNLP/tests/io/pipe/test_cws.py
imports: import pytest
  import os
  from fastNLP.io.pipe.cws import CWSPipe
label_desc: Use image node_id 3 for calling the TestRunCWSPipe obj's underlying member method code with example usage: obj.test_process_from_file_proc() without return types