i am new to AbanteCart but learning gradually,i have a problem with shipping options.i have two shiping options:weight based shipping and pick up from store but the issue is both options don't show on checkout page and when i checkout without the option it brings error:Fatal error: Call to undefined method ACart::areAllFreeShipping() in /home/exafford/public_html/extensions/default_weight/storefront/model/extension/default_weight.php on line 105.please i need ****** help as this store is meant to be launched in a day's time