docs: def _apply_features_filter(self, station_codes):
          """
          If the features filter is set, this will return the intersection of
          those filter items and the given station codes.
          """
          # apply features filter
          if hasattr(self, "features") and self.features is not None:
              station_codes = set(station_codes)
              station_codes = list(
                  station_codes.intersection(set(self.features))
              )
  
          return station_codes