# File lib/less/engine/nodes/property.rb, line 123
      def to_css env = nil
        val = evaluate env
        if val.respond_to? :to_css
          env ? val.to_css(env) : val.to_css
        else
          val.map {|i| env ? i.to_css(env) : i.to_css }.join ', '
        end
      end