code: def rex_text(self, regexp, flags=0, byte=False, default=NULL):
          
  
          # pylint: disable=no-member
          try:
              match = self.rex_search(regexp, flags=flags, byte=byte)
          except DataNotFound:
              if default is NULL:
                  raise DataNotFound('Regexp not found')
              else:
                  return default
          else:
              return normalize_space(decode_entities(match.group(1)))
docs: Search regular expression in response body and return content of first
          matching group.
  
          :param byte: if False then search is performed in
          `response.unicode_body()` else the rex is searched in `response.body`.