code: function (error) {
  
  		if (error) {
  			var err = new Error("set custom data for account [" + account + "] fail");
  			err.name = "setUser Error";
  			LOG.error('set custom data for account [' + account + '] fail', 'user');
  			UTIL.safeCall(onDone, err);
  		}
  		else {
  			LOG.warn('set custom data for account [' + account + '] success', 'user');
  			UTIL.safeCall(onDone, null);
  		}	
  	}
docs: perform DB write-back