# File lib/spreadsheet/format.rb, line 145
    def rotation=(rot)
      if rot.to_s.downcase == 'stacked'
        @rotation_stacked = true
        @rotation = 0
      elsif rot.kind_of?(Integer)
        @rotation_stacked = false
        @rotation = rot % 360
      else
        raise TypeError, "rotation value must be an Integer or the String 'stacked'"
      end
    end