class BlockchainMarketDataDemo {
  private static final Exchange BLOCKCHAIN_EXCHANGE = BlockchainDemoUtils.createExchange();
  private static final ObjectMapper OBJECT_MAPPER =
      new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);

  public static void main(String[] args) throws IOException, InterruptedException {
    System.out.println("===== MARKETDATA SERVICE =====");
    marketDataServiceDemo();
  }

  private static void marketDataServiceDemo() throws IOException {<FILL_FUNCTION_BODY>}
}

    MarketDataService marketDataService = BLOCKCHAIN_EXCHANGE.getMarketDataService();

    System.out.println("===== ORDERBOOK FOR BTC/USD =====");
    Instrument instrument = CurrencyPair.BTC_USD;
    OrderBook orders = marketDataService.getOrderBook(instrument);
    System.out.println(OBJECT_MAPPER.writeValueAsString(orders));
  
<no_super_class>