code: function(oData) {
      // Special case null and undefined
      if(!lang.isValue(oData)) {
          return null;
      }
      
      //Convert to string
      var string = oData + "";
  
      // Validate
      if(lang.isString(string)) {
          return string;
      }
      else {
          YAHOO.log("Could not convert data " + lang.dump(oData) + " to type String", "warn", this.toString());
          return null;
      }
  }
docs: Converts data to type String.
  
  @method DataSourceBase.parseString
  @param oData {String | Number | Boolean | Date | Array | Object} Data to parse.
  The special values null and undefined will return null.
  @return {String} A string, or null.
  @static