Plot size miscalculated.

[yacc2000]

I have multiple data feed, but I want to plot each data feed in individual figure separately.

So base on the idea of this topic:
https://community.backtrader.com/topic/1041/plot-backtesting-results-in-multiple-graphs

I did it in this way:

        for i in range( len(cerebro.datas) ):  # five data feed
            bt_data = cerebro.datas[i]
            for cb_data in cerebro.datas:
                cb_data.plotinfo.plot = False
            bt_data.plotinfo.plot = True  #only plot one data per figure
            if i == 0: #index
                plot_range = None
            else:
                plot_range = stock_data[i]["plotrange"]
            fig2d = cerebro.plot()

But figure size is not correct:

We can see a big blank area under the plot.
The more date feed the bigger blank area:

How could I fix the plot size. Or could anybody please tell me which part of code should I inspect to correct the plot size?

Thanks in advance.