code: def test_fit_notnull(lfrfitmodel):
      """Should not be null."""
      expected = False
      if lfrfitmodel.learned_model is None:
          res = True
      else:
          res = False
      print("numpy:" + str(res))
      assert res == expected
  
file_path: AIF360/tests/test_lfr.py
imports: import os
  import sys
  import numpy
  import pytest
  from aif360.algorithms.preprocessing import LFR
  from aif360.algorithms.preprocessing.optim_preproc_helpers.data_preproc_functions import load_preproc_data_adult
label_desc: Use image node_id 5 for calling a global function with example usage: test_fit_notnull(lfrfitmodel) without return types