# File lib/sprockets/mime.rb, line 9
    def mime_types(ext = nil)
      if ext.nil?
        Rack::Mime::MIME_TYPES.merge(@mime_types)
      else
        ext = Sprockets::Utils.normalize_extension(ext)
        @mime_types[ext] || Rack::Mime::MIME_TYPES[ext]
      end
    end