docstr: For testing if it will raise error
docstr_tok: ["For","testing","if","it","will","raise","error"]
code: def test_multi_proc(self):
      """
      For testing if it will raise error
      """
      iter_n = 2
      pool = Pool(iter_n)
  
      res = []
      for _ in range(iter_n):
          res.append(pool.apply_async(get_features, (self.FIELDS,), {}))
  
      for r in res:
          print(r.get())
  
      pool.close()
      pool.join()
  
file_path: qlib/tests/misc/test_get_multi_proc.py
imports: import unittest
  import qlib
  from qlib.data import D
  from qlib.tests import TestAutoData
  from multiprocessing import Pool
label_desc: Use image node_id 1 for calling the TestGetData obj's underlying member method code with example usage: obj.test_multi_proc() without return types