# File lib/sass/tree/node.rb, line 420
      def selector_to_sass(sel, opts)
        sel.map do |r|
          if r.is_a?(String)
            r.gsub(/(,[ \t]*)?\n\s*/) {$1 ? $1 + "\n" : " "}
          else
            "\#{#{r.to_sass(opts)}}"
          end
        end.join
      end