python用openpyxl画散点图次坐标轴异常

使用python，openpyxl脚本画散点图的时候用下面命令合并两个图标，设置次坐标轴，但是实际还是只有一个坐标轴。

chart1.y_axis.crosses = "max"
chart1 += chart2
ws.add_chart(chart1, "D1")

麻烦帮忙看下是什么问题？

源码如下

from openpyxl import Workbook
from openpyxl.chart import (ScatterChart,Reference,Series)

listx = [i for i in range(100)]
listy = [i * 2 for i in range(100)]
listz = [i ** 2 for i in range(100)]

wb = Workbook()
ws =wb.active
ws['B1'] = 'y=x*2'
ws['C1'] = 'y=x^2'
for i in range(100):
ws['A' + str(i+2)] = listx[i]
ws['B' + str(i+2)] = listy[i]
ws['C' + str(i+2)] = listz[i]

chart1 = ScatterChart()
chart1.title1 = "Double Chart"
chart1.x_axis.title = 'x'
chart1.y_axis.title = 'f(x)=x*2'
xvalues = Reference(ws, min_col=1, min_row=2, max_row=100)
values1 = Reference(ws, min_col=2, min_row=1, max_row=100)
series1 = Series(values1, xvalues, title_from_data=False)
chart1.append(series1)

chart2 = ScatterChart()
chart2.y_axis.title = 'f(x)=x^2'
xvalues = Reference(ws, min_col=1, min_row=2, max_row=100)
values2 = Reference(ws, min_col=3, min_row=1, max_row=100)
series2 = Series(values2, xvalues, title_from_data=False)
chart2.append(series2)

chart1.y_axis.crosses = "max"
chart1 += chart2
ws.add_chart(chart1, "D1")
wb.save('plot.xlsx')

运行结果