code: def test_apply_proc(self):
      data = DataSet(
          {
              "x": ["xxxxas1w xw zxw xz", "xxxxas1w xw zxw xz"] * 100,
              "y": [0, 1] * 100,
          }
      )
      data.apply_field(
          lambda x: len(x),
          field_name="x",
          new_field_name="len_x",
          num_proc=0,
      )
  
imports: import os
  import pytest
  import numpy
  from fastNLP.core.dataset import DataSet, FieldArray, Instance, ApplyResultException
  from fastNLP import logger
label_desc: Use image node_id 32 for calling the TestDataSetMethods obj's underlying member method code with example usage: obj.test_apply_proc() without return types