code: private void updateReservableForChargingStation(ChargingStationId chargingStationId, boolean reservable) {
          ChargingStation chargingStation = getChargingStation(chargingStationId);
  
          if (chargingStation != null) {
              chargingStation.setReservable(reservable);
              chargingStationRepository.createOrUpdate(chargingStation);
          }
      }
docs: Updates the 'reservable' property of the charging station. If the charging station cannot be found in the
  repository an error is logged.
  
  @param chargingStationId charging station identifier.
  @param reservable        true if the charging station is reservable, false otherwise.