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Can you provide a code to 3 看跌合约的回测 and the other steps required given the following:
3 看跌合约的回测
看跌合约的回测首先需要一个看跌买入因子，下面的代码即示例向下突破做为买入因子的put策略："
Please write code following the instructions in jupyter notebook style.
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#Here is code to 3 看跌合约的回测 and the other steps required.

from abupy import AbuFactorBuyXD, BuyPutMixin

class AbuFactorBuyPutXDBK(AbuFactorBuyXD, BuyPutMixin):
    """示例继承AbuFactorBuyXD完成反向突破买入择时类"""
    def fit_day(self, today):
        """
        针对每一个交易日拟合买入交易策略，寻找向上突破买入机会
        :param today: 当前驱动的交易日金融时间序列数据
        """
        # 与AbuFactorBuyBreak区别就是买向下突破的，即min()
        if today.close == self.xd_kl.close.min():
            return self.buy_tomorrow()
        return None
    
# 通过import的方式导入AbuFactorBuyPutBreak，因为在windows系统上，启动并行后，在ipython notebook中定义的类会在子进程中无法找到
from abupy import AbuFactorBuyPutBreak