code: def test_whitespace_tokenizer(self):
      self.nlp.tokenizer = WhitespaceTokenizer(self.nlp.vocab)
      text = "don't split this contraction."
      doc = self.nlp(text)
  
      assert [t.text for t in doc] == text.split(" ")
  
imports: import unittest
  import spacy
  from scispacy.util import WhitespaceTokenizer
label_desc: Use image node_id 2 for calling the TestUtil obj's underlying member method code with example usage: obj.test_whitespace_tokenizer() without return types