# File lib/css_parser/parser.rb, line 185
    def add_rule_set!(ruleset, media_types = :all)
      raise ArgumentError unless ruleset.kind_of?(CssParser::RuleSet)

      media_types = [media_types] unless Array === media_types
      media_types = media_types.flat_map { |mt| CssParser.sanitize_media_query(mt)}

      @rules << {:media_types => media_types, :rules => ruleset}
    end