def difference(**options)
      if positive?
        number_to_currency absolute, format: '+%u%n', **options
      else
        number_to_currency absolute, **options
      end
    end
def difference(**options)
      if positive?
        number_to_currency absolute, format: '+%u%n', **options
      else
        number_to_currency absolute, **options
      end
    end
TODO: This shouldn't necessarily return a currency representation.

 Returns Comparator#absolute presented as currency.