下面的代码使用openpyxl生成了一个简单的条形图。

我希望能够在Y轴上着色标题。但我找不到一个有效的解决方案。有人知道怎么做吗？
我的目标很简单：

import openpyxl
from openpyxl.chart import BarChart, Reference

# Create a workbook and activate a sheet
wb = openpyxl.Workbook()
sheet = wb.active

# insert some categories
cell = sheet.cell(row=1, column=1)
cell.value = 'Category 1.1' 
cell = sheet.cell(row=2, column=1)
cell.value = 'Category 1.2 - limit'
cell = sheet.cell(row=3, column=1)
cell.value = 'Category 2'
cell = sheet.cell(row=4, column=1)
cell.value = 'Category 2.1 - extra'
cell = sheet.cell(row=5, column=1)
cell.value = 'Category 2.2 - extra2'

# insert some values
for i in range(5):
    cell = sheet.cell(row=i+1, column=2)
    cell.value = i+2

# create chart
chart = BarChart()

values = Reference(sheet, min_col = 2, min_row = 1,
                         max_col = 2, max_row = 5)

bar_categories = Reference(sheet, min_col=1, min_row=1, max_row=5)
chart.add_data(values)
chart.set_categories(bar_categories)

chart.title = " BAR-CHART "
chart.legend = None
chart.x_axis.title = " X_AXIS "
chart.y_axis.title = " Y_AXIS "
sheet.add_chart(chart, "E2")
 
# save the file
wb.save("barChart.xlsx")