Wish to plot LineBuffer object in the main figure

[fanpeix]

I need to plot self.U and self.D in the main figure, here is the code

        # 指标计算
        self.HH = bt.ind.Highest(self.high, period=self.p.period, subplot=False, plot=False)     # N日high的最高价
        self.LC = bt.ind.Lowest(self.close, period=self.p.period, subplot=False, plot=False)     # N日close的最低价
        self.HC = bt.ind.Highest(self.close, period=self.p.period, subplot=False, plot=False)    # N日close的最高价
        self.LL = bt.ind.Lowest(self.low, period=self.p.period, subplot=False, plot=False)       # N日low的最低价
        self.range = bt.ind.Highest((self.HH - self.LC), (self.HC - self.LL), subplot=False, plot=False)
        self.U = self.open + self.p.upper_factor * self.range             # 上轨
        self.D = self.open - self.p.lower_factor * self.range            # 下轨


        # WISH TO PLOT THESE TWO OBJECTS!!
        self.U.plotinfo.plot = True
        self.D.plotinfo.plot = True


        # 计算突破
        self.crossover_up = bt.ind.CrossOver(self.close, self.lines.U, subplot=False, plot=False)
        self.crossover_dn = bt.ind.CrossOver(self.close, self.lines.D, subplot=False, plot=False)

and it returned:

  File "C:/Users/Administrator/PycharmProjects/backtrader_coin/strategies/dual_thrust.py", line 63, in __init__
    self.U.plotinfo.plot = True
AttributeError: 'LinesOperation' object has no attribute 'plotinfo'

how can I achieve that?