def to_base_unit
      case @unit
      when :centimeter
        OoxmlSize.new(@value * 360_000)
      when :point
        OoxmlSize.new(@value * 12_700)
      when :half_point
        OoxmlSize.new(@value * (12_700 / 2))
      when :one_eighth_point
        OoxmlSize.new(@value * (12_700 / 8))
      when :one_100th_point
        OoxmlSize.new(@value * (12_700 / 100))
      when :one_240th_cm
        OoxmlSize.new(@value * 1500)
      when :dxa, :twip
        return OoxmlSize.new(@value * 635, :emu)
      when :inch
        OoxmlSize.new(@value * 914_400, :emu)
      when :spacing_point
        OoxmlSize.new(@value * (12_700 / 100), :emu)
      when :percent
        OoxmlSize.new(@value * 100_000, :one_100000th_percent)
      when :pct
        OoxmlSize.new(@value * 100_000 / 50, :one_100000th_percent)
      when :one_1000th_percent
        OoxmlSize.new(@value * 100, :one_100000th_percent)
      else
        self
      end
    end
def to_base_unit
      case @unit
      when :centimeter
        OoxmlSize.new(@value * 360_000)
      when :point
        OoxmlSize.new(@value * 12_700)
      when :half_point
        OoxmlSize.new(@value * (12_700 / 2))
      when :one_eighth_point
        OoxmlSize.new(@value * (12_700 / 8))
      when :one_100th_point
        OoxmlSize.new(@value * (12_700 / 100))
      when :one_240th_cm
        OoxmlSize.new(@value * 1500)
      when :dxa, :twip
        return OoxmlSize.new(@value * 635, :emu)
      when :inch
        OoxmlSize.new(@value * 914_400, :emu)
      when :spacing_point
        OoxmlSize.new(@value * (12_700 / 100), :emu)
      when :percent
        OoxmlSize.new(@value * 100_000, :one_100000th_percent)
      when :pct
        OoxmlSize.new(@value * 100_000 / 50, :one_100000th_percent)
      when :one_1000th_percent
        OoxmlSize.new(@value * 100, :one_100000th_percent)
      else
        self
      end
    end
Convert all values to one same base unit
 @return [OoxmlSize] base unit