# File lib/tour/facets/integer/roman.rb, line 24
  def roman
    int = self
    #return nil if integer > ROMAN_MAX
    return "-#{(-int).roman}" if int < 0
    return "" if int == 0
    ROMAN_VALUES.each do |(i, v)|
      return(i + (int-v).roman) if v <= int 
    end
  end