code: def test_proc_count_nest_env():
      with set_env_var("LK_NUM_PROCS", "7,3"):
          assert proc_count() == 7
          assert proc_count(level=1) == 3
          assert proc_count(level=2) == 1
  
imports: import os
  import logging
  import multiprocessing
  import numpy
  import pytest
  from seedbank import root_seed
  from lenskit.util.parallel import invoker, proc_count, run_sp, is_worker, is_mp_worker
  from lenskit.util.test import set_env_var
  from lenskit.sharing import persist, SHM_AVAILABLE
  from pytest import mark, raises, approx
label_desc: Use image node_id 9 for calling a global function with example usage: test_proc_count_nest_env() without return types