docs: def _prepare_text(self, text):
          """Returns `text` with each consituent token wrapped in HTML markup
          for later match annotation.
  
          :param text: text to be marked up
          :type text: `str`
          :rtype: `str`
  
          """
          # Remove characters that should be escaped for XML input (but
          # which cause problems when escaped, since they become
          # tokens).
          text = re.sub(r'[<>&]', '', text)
          pattern = r'({})'.format(self._tokenizer.pattern)
          return re.sub(pattern, self._base_token_markup, text)