Outer group removes multiple inner groups

I want to have multiple groups on outline level 1 and over these groups I want to have 1 group which is on outline level 2, like that:

But with my code the outer group always "overwrites" or removes the inner groups:

Code

import openpyxl

wb = openpyxl.load_workbook("Planung.xlsx")
ws = wb["Zeitplan"]
ws.sheet_properties.outlinePr.summaryBelow = False

ws.row_dimensions.group(9, 11, outline_level=1)
ws.row_dimensions.group(13, 13, outline_level=1)
ws.row_dimensions.group(16, 17, outline_level=1)
ws.row_dimensions.group(7, 17, outline_level=2)

wb.save('test.xlsx')

Reproduction steps

• Create file called Planung.xlsx
• Create sheet called Zeitplan in the created workbook
• Run code
• Open test.xlsx

>Solution :

There is a problem with the rank of your outline_levels, which messes up the nesting.

Here is a possible fix :

import openpyxl

wb = openpyxl.load_workbook("Planung.xlsx")
ws = wb["Zeitplan"]

ws.sheet_properties.outlinePr.summaryBelow = False

ws.row_dimensions.group(7, 17, outline_level=1)
ws.row_dimensions.group(9, 11, outline_level=2)
ws.row_dimensions.group(13, 13, outline_level=2)
ws.row_dimensions.group(16, 17, outline_level=2)

wb.save("test.xlsx")

Output :