# File lib/facet/lisp-format.rb, line 872
        def roman_helper(n, table)
          unless n.is_a? Fixnum
            arg_error 'only Fixnum values can be converted to roman numerals'
          end
          out = []
          table.each do |decimal, roman|
            q, r = n.divmod(decimal)
            if q > 0
              out << roman * q
              n = r
            end
          end
          out.join('')
        end