code: def test_exclude_test_files(self):
      self.create_file("sample_test.py", "print('Hello')\n")
      loc = count_loc(self.test_dir, exclude=("_test",))
      self.assertEqual(loc, 0)
  
imports: import os
  import sys
  from io import StringIO
  from keras.testing import test_case
  from keras.utils.code_stats import count_loc
label_desc: Use image node_id 5 for calling the TestCountLoc obj's underlying member method code with example usage: obj.test_exclude_test_files() without return types