code: def test_nfev_workers(params_lmfit):
      """TEST 12: make sure the nfev is correct for workers != 1."""
      mini = lmfit.Minimizer(func_lmfit, params_lmfit, workers=-1)
      out = mini.minimize(method="brute")
      assert_equal(out.nfev, 20 ** len(out.var_names))
  
imports: import pickle
  import numpy
  from numpy.testing import assert_allclose, assert_equal
  import pytest
  from scipy import optimize
  import lmfit
label_desc: Use image node_id 15 for calling a global function with example usage: test_nfev_workers(params_lmfit) without return types