def scale=(attrs)
      @scale = if attrs[:function_code]
        Functional.new(attrs[:value], attrs[:unit_code], attrs[:function_code])
      else
        Scale.new(attrs[:value], attrs[:unit_code])
      end
    end
def scale=(attrs)
      @scale = if attrs[:function_code]
        Functional.new(attrs[:value], attrs[:unit_code], attrs[:function_code])
      else
        Scale.new(attrs[:value], attrs[:unit_code])
      end
    end
Set the atom's scale. It can be set as a Scale or a Functional
 @return [Unitwise::Functional, Unitwise::Scale]
 @api public