การเขียน non-public method

class Document:
  def __init__(self, text):
    self.text = text
    # pre tokenize the document with non-public tokenize method
    self.tokens = self._tokenize()
    # pre tokenize the document with non-public count_words
    self.word_counts = self.____()

  def _tokenize(self):
    return tokenize(self.text)
	
  # non-public method to tally document's word counts with Counter
  def ____(self):
    return ____(____.tokens)