code: def test_whitespace_only(self):
      self.create_file("whitespace.py", "     \n\t\n")
      loc = count_loc(self.test_dir)
      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 9 for calling the TestCountLoc obj's underlying member method code with example usage: obj.test_whitespace_only() without return types