if (isset($params['listing_amount']) && (is_numeric($params['listing_amount']))) {
$listing_amount=$params['listing_amount'];
} else {$listing_amount=DEFAULT_LISTING_AMOUNT;}
if (isset($params['listing_amount']) && (is_numeric($params['listing_amount']))) {
$listing_amount=$params['listing_amount'];
} else {$listing_amount=DEFAULT_LISTING_AMOUNT;}