code: def test_process_from_file_proc(self, num_proc=2):
      for pipe in [
          YelpPolarityPipe,
          SST2Pipe,
          IMDBPipe,
          YelpFullPipe,
          SSTPipe,
      ]:
          print(pipe)
          data_bundle = pipe(
              tokenizer="raw", num_proc=num_proc
          ).process_from_file()
          print(data_bundle)
  
file_path: fastNLP/tests/io/pipe/test_classification.py
imports: import pytest
  import os
  from fastNLP.io import DataBundle
  from fastNLP.io.pipe.classification import SSTPipe, SST2Pipe, IMDBPipe, YelpFullPipe, YelpPolarityPipe, AGsNewsPipe, DBPediaPipe
  from fastNLP.io.pipe.classification import ChnSentiCorpPipe, THUCNewsPipe, WeiboSenti100kPipe
label_desc: Use image node_id 2 for calling the TestClassificationPipe obj's underlying member method code with example usage: obj.test_process_from_file_proc(num_proc) without return types