code: function (hash /*:Object*/) /*:String*/ {
          
          //shortcuts
          var lang = YAHOO.lang;
          
          if (!lang.isObject(hash)){
              throw new TypeError("Cookie._createCookieHashString(): Argument must be an object.");
          }
          
          var text /*:Array*/ = [];
          
          for (var key in hash){
              if (lang.hasOwnProperty(hash, key) && !lang.isFunction(hash[key]) && !lang.isUndefined(hash[key])){
                  text.push(encodeURIComponent(key) + "=" + encodeURIComponent(String(hash[key])));
              }
          }
          
          return text.join("&");
      }
docs: Formats a cookie value for an object containing multiple values.
  @param {Object} hash An object of key-value pairs to create a string for.
  @return {String} A string suitable for use as a cookie value.
  @method _createCookieHashString
  @private
  @static