code: def boundary_words(seq):
      '''
      Wraps all word transitions with a boundary token character (\x00).
  
      Arguments:
      - `seq`:
      '''
      in_word = None
      for char in seq:
          if char == '\x00' and in_word is not None:
              in_word = not in_word
          elif char in WHITESPACE_CHARS:
              if in_word is not None and in_word:
                  yield '\x00'
              in_word = False
          else:
              if in_word is not None and not in_word:
                  yield '\x00'
              in_word = True
          yield chaf boundary_words(seq):
      '''
      Wraps all word transitions with a boundary token character (\x00).
  
      Arguments:
      - `seq`:
      '''
      in_word = None
      for char in seq:
          if char == '\x00' and in_word is not None:
              in_word = not in_word
          elif char in WHITESPACE_CHARS:
              if in_word is not None and in_word:
                  yield '\x00'
              in_word = False
          else:
              if in_word is not None and not in_word:
                  yield '\x00'
              in_word = True
          yield char
docs: Wraps all word transitions with a boundary token character (\x00).
  
      Arguments:
      - `seq`: