code: function background(options) {
      options = options || {};
      // ReSharper disable once UnusedParameter
      return function (config) {
          var values = [];
          [
              'attachment',
              'clip',
              'color',
              'image',
              'origin',
              'position',
              'repeat',
              'size'
          ].forEach(function (prop) {
              if (options.hasOwnProperty(prop)) {
                  values.push(options[prop]);
              }
          });
          if (values.length) {
              return [['background', values.join(' ')]];
          }
          return [];
      };
  }
docs: ReSharper disable once UnusedLocals