Using Premise with CustomPress

Hi. I'm trying to use the Premise plugin (from Copyblogger Media) to set up a private members area on the above-referenced website. Among other things, I would like to make the custom posts I create using CustomPress functionality (the custom post type is called "college") accessible only to paying members.

I asked the support team at Copyblogger Media and they said I should add this code:

$post_type=college //replace this with the name of your custom post type
add_action('init', 'add_premise_member_support');
function add_premise_member_support() {
  add_post_type_support( $post_type, 'premise-member-access' );


to the functions.php file of the theme I am using. But they also noted that I should ask the developer of the plugin (in this case, WPMU DEV) how you handle additional code for custom post types created with the CustomPress plugin.

Can you tell me exactly where in the functions.php file I would add that code?

Thanks in advance for any help you can offer - I really appreciate it.