Anyone know why this is not adding borders to my sheet

Anyone know why this is not adding borders to my sheet?

        thick = Side(border_style="thick", color='FF0707')
        ws['F1'].border = Border(top=thick, left=thick, right=thick, bottom=thick)
        for row in ws['A1:D10']:
            for cell in row:
                cell.border = Border(top=thick, left=thick, right=thick, bottom=thick)