How to use the prophet.orders.Order function in prophet

price_generator = YahooData('Adj Close', 'prices', cache_path=CACHE_PATH)
    prophet.register_data_generators(price_generator)
    prophet.set_order_generator(OrderGenerator())
    backtest = prophet.run_backtest(start=datetime(2010, 1, 1),
                                    end=datetime(2014, 11, 21))

    prophet.register_portfolio_analyzers(default_analyzers)
    analysis = prophet.analyze_backtest(backtest)
    assert round(analysis['sharpe'], 10) == 1.0970973495
    assert round(analysis['average_return'], 10) == 0.0010547843
    assert round(analysis['cumulative_return'], 10) == 2.1688171559
    assert round(analysis['volatility'], 10) == 0.0152622562

    today = datetime(2014, 11, 10)
    expected_orders = Orders(Order(symbol='AAPL', shares=100))
    assert prophet.generate_orders(today) == expected_orders