php snippet not working

I have the following php snippet I want to use for my site. If I add the snippet directly to the theme functions.php file, the snippet works fine but if I add it to my install of WPCode Lite it doesn’t work. I have other php snippets I have added to WPCode Lite that work fine so I’m not sure why this one won’t work.

the code:

add_action( 'woocommerce_order_status_processing_to_on-hold', 'enable_processing_to_on_hold_notification', 10, 2 );
function enable_processing_to_on_hold_notification( $order_id, $order ){
    // Getting all WC_emails array objects
    $mailer = WC()->mailer()->get_emails();

    // Send the "On Hold" notification
    $mailer['WC_Email_Customer_On_Hold_Order']->trigger( $order_id );
}

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