Is there an option to hide gridlines?
I tried ws.show_gridlines = False, and it has no affect on the output.
This is now possible in version 2.2 by setting the showGridlines attribute of a worksheet's sheet_view.
from openpyxl import Workbook
wb = Workbook()
ws = wb.active
ws.sheet_view.showGridLines = False
Fixed in 2.2