private function get_membership_units()
 {
     global $cart, $cookie;
     $unis = 1;
     if (Module::isInstalled('agilemembership')) {
         include_once _PS_ROOT_DIR_ . "/modules/agilemembership/MembershipType.php";
         $products = $cart->getProducts();
         if (count($products) == 1) {
             $membershiptype = MembershipType::getMembershipTypeByProductID(intval($products[0]['id_product']), $cart->id_lang);
             if (isset($membershiptype) and intval($membershiptype['units']) > 0) {
                 $unis = intval($membershiptype['units']);
             }
         }
     }
     return $unis;
 }