code: function (name /*:String*/, subName /*:String*/, value /*:Variant*/, options /*:Object*/) /*:String*/ {
          
          var lang = YAHOO.lang;
          
          if (!lang.isString(name) || name === ""){
              throw new TypeError("Cookie.setSub(): Cookie name must be a non-empty string.");
          }
          
          if (!lang.isString(subName) || subName === ""){
              throw new TypeError("Cookie.setSub(): Subcookie name must be a non-empty string.");
          }
          
          if (lang.isUndefined(value)){
              throw new TypeError("Cookie.setSub(): Subcookie value cannot be undefined.");
          }
          
          var hash /*:Object*/ = this.getSubs(name);
          
          if (!lang.isObject(hash)){
              hash = {};
          }
          
          hash[subName] = value;
          
          return this.setSubs(name, hash, options);
          
      }
docs: Sets a sub cookie with a given name to a particular value.
  @param {String} name The name of the cookie to set.
  @param {String} subName The name of the subcookie to set.
  @param {Variant} value The value to set.
  @param {Object} options (Optional) An object containing one or more
  cookie options: path (a string), domain (a string), expires (a Date object),
  and secure (true/false).
  @return {String} The created cookie string.
  @method setSub
  @static