def style=(style)
      each_with_index do | cell, index |
        cell.style = style.is_a?(Array) ? style[index] : style
      end
    end
def style=(style)
      each_with_index do | cell, index |
        cell.style = style.is_a?(Array) ? style[index] : style
      end
    end
sets the style for every cell in this row