Fatal error: Uncaught TypeError: usort(): Argument #1 ($array) must be of type array, null given in /home/site/wwwroot/wp-content/themes/nmbtc/helpers/filter-helper.php:13 Stack trace: #0 /home/site/wwwroot/wp-content/themes/nmbtc/helpers/filter-helper.php(13): usort(NULL, Object(Closure)) #1 /home/site/wwwroot/wp-content/themes/nmbtc/mvc/controller/product-categories-controller.php(250): SpeedTheme\Helpers\FilterHelper::getFilters(Array) #2 /home/site/wwwroot/wp-content/themes/nmbtc/taxonomy-product-category.php(13): SpeedTheme\Mvc\Controller\ProductCategoriesController::loadProductCategoryByType(256, 'series_list') #3 /home/site/wwwroot/wp-includes/template-loader.php(106): include('/home/site/wwwr...') #4 /home/site/wwwroot/wp-blog-header.php(19): require_once('/home/site/wwwr...') #5 /home/site/wwwroot/index.php(17): require('/home/site/wwwr...') #6 {main} thrown in /home/site/wwwroot/wp-content/themes/nmbtc/helpers/filter-helper.php on line 13