Detect if a visitor is a "Paid Customer"

I can detect if a visitor is logged in or not by
$lite = Am_Lite::getInstance();
if($lite->isLoggedIn()){...}
How can I detect if a visitor is a "Paid Customer" or not in a similiar fashion?

Try

Am_Lite::getInstance()->haveSubscriptions($search)
returns true if user have active subscription to $search

Or

constant Am_Lite::ANY - subscription to any product

Works fine, thanks.