code: def format(self, response):
          
  
          res = self._prepare_response(response)
          res.content = self._format_data(res.content, self.charset)
          return self._finalize_response(res)
docs: Format the data.
  
          In derived classes, it is usually better idea to override
          ``_format_data()`` than this method.
  
          :param response: devil's ``Response`` object or the data
                           itself. May also be ``None``.
          :return: django's ``HttpResponse``
  
          todo: this shouldn't change the given response. only return the
          formatted response.