    # File lib/compass/sass_extensions/functions/selectors.rb, line 48
      def headers(from = nil, to = nil)
        if from && !to
          if from.is_a?(Sass::Script::String) && from.value == "all"
            from = Sass::Script::Number.new(1)
            to = Sass::Script::Number.new(6)
          else
            to = from
            from = Sass::Script::Number.new(1)
          end
        else
          from ||= Sass::Script::Number.new(1)
          to ||= Sass::Script::Number.new(6)
        end
        Sass::Script::String.new((from.value..to.value).map{|n| "h#{n}"}.join(", "))
      end