code: def test_open_file_non_existent_file_object(self):
      file_obj = None
      with self.assertRaises(Exception):
          with utils.open_file(file_obj):
              pass
  
imports: import logging
  import unittest
  import numpy
  from gensim import utils
  from gensim.test.utils import datapath, get_tmpfile
label_desc: Use image node_id 5 for calling the TestUtils obj's underlying member method code with example usage: obj.test_open_file_non_existent_file_object() without return types