Fatal error: Uncaught TypeError: method_exists(): Argument #1 ($object_or_class) must be of type object|string, null given in /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-content/plugins/groupby-for-woocommerce/public/class-wc-groupbuy-public.php:828
Stack trace:
#0 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-content/plugins/groupby-for-woocommerce/public/class-wc-groupbuy-public.php(828): method_exists(NULL, 'get_type')
#1 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-includes/class-wp-hook.php(309): wc_groupbuy_Public->add_post_class(Array)
#2 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-includes/plugin.php(189): WP_Hook->apply_filters(Array, Array)
#3 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-includes/post-template.php(581): apply_filters('post_class', Array, Array, 3447)
#4 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-includes/post-template.php(459): get_post_class(Array, NULL)
#5 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-content/themes/storefront/content-page.php(10): post_class()
#6 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-includes/template.php(772): require('/homepages/31/d...')
#7 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-includes/template.php(716): load_template('/homepages/31/d...', false, Array)
#8 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-includes/general-template.php(204): locate_template(Array, true, false, Array)
#9 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-content/themes/storefront/page.php(24): get_template_part('content', 'page')
#10 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-includes/template-loader.php(106): include('/homepages/31/d...')
#11 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-blog-header.php(19): require_once('/homepages/31/d...')
#12 /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/index.php(17): require('/homepages/31/d...')
#13 {main}
thrown in /homepages/31/d841462698/htdocs/clickandbuilds/AliMall/wp-content/plugins/groupby-for-woocommerce/public/class-wc-groupbuy-public.php on line 828