code: def test_mixed_threads_processes(x):
      # Test that the fft threadpool is safe to use before & after fork
  
      expect = fft.fft(x, workers=2)
  
      with multiprocessing.Pool(2) as p:
          res = p.map(_mt_fft, [x for _ in range(4)])
  
      for r in res:
          assert_allclose(r, expect)
  
      fft.fft(x, workers=2)
  
file_path: scipy/scipy/fft/tests/test_multithreading.py
imports: from scipy import fft
  import numpy
  import pytest
  from numpy.testing import assert_allclose
  import multiprocessing
  import os
label_desc: Use image node_id 4 for calling a global function with example usage: test_mixed_threads_processes(x) without return types