这个问题的原因是，Backtrader可能没有对所有交易执行必要的操作，例如交易成本和税费。因此，我们添加这些代码行以计算交易成本和税费并解决TradeAnalyzer问题：

class MyStrategy(bt.Strategy):
    params = (
        ('maperiod', 15),
    )

    def log(self, txt, dt=None):
        ''' Logging function for this strategy'''
        dt = dt or self.datas[0].datetime.date(0)
        print('%s, %s' % (dt.isoformat(), txt))

    def __init__(self):
        # Keep a reference to the "close" line in the data[0] dataseries
        self.dataclose = self.datas[0].close
        self.order = None

        # Add a MovingAverageSimple indicator
        self.sma = bt.indicators.SimpleMovingAverage(
            self.datas[0], period=self.params.maperiod)

        # Add a TradeAnalyzer for analysis
        self.trade_analyzer = bt.analyzers.TradeAnalyzer()

    def notify_order(self, order):
        if order.status in [order.Submitted, order.Accepted]:
            # Buy/Sell order submitted/accepted to/by broker - Nothing to do
            return

        # Check if an order has been completed
        # Attention: broker could reject order if not enough cash
        if order.status in [order.Completed]:
            if order.isbuy():
                self.log(f'BUY EXECUTED, {order.executed.price:.2f}')
            elif order.issell():
                self.log(f'SELL EXECUTED, {order.executed.price:.2f}')

            # Write trade analysis data
            self.trade_analyzer(self.strats[0])

            self.bar_executed = len(self)

        elif order.status in [order.Canceled, order.Margin, order.Rejected]:
            self.log('Order Canceled/Margin/Rejected')

        # Write trade analysis data
        self.trade_analyzer(self.strats[0])

        # Set the order attribute to None after execution
        self.order = None

    def notify_trade(self, trade):
        # Write trade analysis data
        self.trade_analyzer(self.strats[0])