def border_widths
         widths = []
         @borders.each {|entry| widths.push(entry.nil? ? 0 : entry)}
         widths
      end
def border_widths
         widths = []
         @borders.each {|entry| widths.push(entry.nil? ? 0 : entry)}
         widths
      end
This method retrieves an array with the cell border width settings.
 The values are inserted in top, right, bottom, left order.