parameters

Coming from a previous problem, I finally decided to just code my own condition, and the condition is working properly so far. Except for one thing, that is. There is one optional parameter I would like to add to my condition; basically, I'd like to let the user specify the content types he/she would like to restrict, if any. So, my condition function is as follow:

<?php
/**
* Implementation of hook_rules_condition_info().
*/
function nodecount_rules_condition_info() {
$conditions = array();
$conditions['nodecount_rules_condition'] = array(
'group' => t('Nodes'),