'And' object has no attribute 'size'

[qicqic99]

I get an error when plotting figure with bt.And or bt.If, but it work successfully without it.

def init(self):

    self.order = None
    self.dataclose = self.datas[0].close
    self.ADXPlus3 = ADXDIPlus3(period=self.p.period, subplot=True,)
    self.DIplus = btind.PlusDirectionalIndicator (self.data, period=self.p.pperiod, plotmaster=self.ADXPlus3)
    self.adx_sig = btind.CrossOver(self.ADXPlus3, 20)
    self.final_sig = bt.And(self.adx_sig, self.vol_sig, btind.CrossOver(self.DIplus, 30))

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-4-5b5037e58587> in <module>
     34 cerebro.run()
     35 # cerebro.plot(iplot=True)
---> 36 cerebro.plot(b, iplot=False)
     37 print('Final Portfolio Value: %.2f' % cerebro.broker.getvalue())

c:\users\user\virturalpythonenv\inode\lib\site-packages\backtrader\cerebro.py in plot(self, plotter, numfigs, iplot, start, end, width, height, dpi, tight, use, **kwargs)
    989                 rfig = plotter.plot(strat, figid=si * 100,
    990                                     numfigs=numfigs, iplot=iplot,
--> 991                                     start=start, end=end, use=use)
    992                 # pfillers=pfillers2)
    993 

c:\users\user\virturalpythonenv\inode\lib\site-packages\backtrader_plotting\bokeh\bokeh.py in plot(self, obj, figid, numfigs, iplot, start, end, use, fill_data, tradingdomain, **kwargs)
    510             self._blueprint_strategy(obj, start, end, tradingdomain, **kwargs)
    511             if fill_data:
--> 512                 df: pd.DataFrame = self.build_strategy_data(obj, start, end)
    513 
    514                 new_cds = ColumnDataSource.from_df(df)

c:\users\user\virturalpythonenv\inode\lib\site-packages\backtrader_plotting\bokeh\bokeh.py in build_strategy_data(self, strategy, start, end, num_back, startidx)
    472         for obj in itertools.chain(strategy.getindicators(), strategy.getobservers()):
    473 
--> 474             for lineidx in range(obj.size()):
    475                 line = obj.lines[lineidx]
    476                 source_id = FigureEnvelope._source_id(line)

AttributeError: 'And' object has no attribute 'size'