How to make outline to the top?

Question

import xlsxwriter

workbook = xlsxwriter.Workbook('outline_collapsed_test.xlsx')
worksheet1 = workbook.add_worksheet('Outlined Rows')

worksheet1.set_row(2, None, None, {'level': 2})
worksheet1.set_row(3, None, None, {'level': 2})
worksheet1.set_row(4, None, None, {'level': 2})
worksheet1.set_row(5, None, None, {'level': 1})

worksheet1.set_row(6, None, None, {'level': 2})
worksheet1.set_row(7, None, None, {'level': 2})
worksheet1.set_row(8, None, None, {'level': 2})
worksheet1.set_row(9, None, None, {'level': 1})

workbook.close()

this code place symbol '+' on the bottom. How to move it to the top? like this

Answer 1

http://msdn.microsoft.com/ru-ru/library/documentformat.openxml.spreadsheet.outlineproperties.aspx

worksheet1.outline_settings(outline_below = 0)