code: def test_should_tokenize_only_white_spaces(self):
      # Given
      text = "    "
      language = LANGUAGE_EN
  
      # When
      tokens = tokenize(text, language)
  
      # Then
      self.assertListEqual(tokens, [])
  
file_path: snips-nlu/snips_nlu/tests/test_preprocessing.py
imports: from __future__ import unicode_literals
  from snips_nlu_parsers import get_all_languages
  from snips_nlu.constants import LANGUAGE_EN
  from snips_nlu.preprocessing import Token, tokenize
  from snips_nlu.tests.utils import SnipsTest
label_desc: Use image node_id 2 for calling the TestPreprocessing obj's underlying member method code with example usage: obj.test_should_tokenize_only_white_spaces() without return types