code: def add_properties(self):
          
          for property_name in [p[0] for p in inspect.getmembers(self.__class__) if isinstance(p[1], property)]:
              self._results_fields[property_name] = getattr(self, property_name, None)
docs: Called during post processing of result
          Any properties defined in your subclass will get exposed as members of the result json from the search