    # File lib/core-uncommon/facets/integer/roman.rb, line 54
      def roman
        roman = upcase
        raise unless roman?
        last = roman[-1,1]
        roman.reverse.split('').inject(0) do |result, c|
          if ROMAN_VALUES[c] < ROMAN_VALUES[last]
            result -= ROMAN_VALUES[c]
          else
            last = c
            result += ROMAN_VALUES[c]
          end
        end
      end