code: def _do_search(self):
          
          if self._results_cache is None:
              response = self.raw()
              results = self.to_python(response.get('hits', {}).get('hits', []))
              self._results_cache = DictSearchResults(
                  self.type, response, results, None)
          return self._results_cache
docs: Perform the mlt call, then convert that raw format into a
          SearchResults instance and return it.