Fatal error: Uncaught Error: Undefined constant "is_single" in /home/dmg165pk/public_html/wp-content/themes/storefront-child/functions.php:740 Stack trace: #0 /home/dmg165pk/public_html/wp-includes/class-wp-hook.php(308): remove_page_wise('') #1 /home/dmg165pk/public_html/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array) #2 /home/dmg165pk/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #3 /home/dmg165pk/public_html/wp-includes/script-loader.php(2180): do_action('wp_enqueue_scri...') #4 /home/dmg165pk/public_html/wp-includes/class-wp-hook.php(308): wp_enqueue_scripts('') #5 /home/dmg165pk/public_html/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array) #6 /home/dmg165pk/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #7 /home/dmg165pk/public_html/wp-includes/general-template.php(3043): do_action('wp_head') #8 /home/dmg165pk/public_html/wp-content/themes/storefront/header.php(18): wp_head() #9 /home/dmg165pk/public_html/wp-includes/template.php(783): require_once('/home/dmg165pk/...') #10 /home/dmg165pk/public_html/wp-includes/template.php(718): load_template('/home/dmg165pk/...', true, Array) #11 /home/dmg165pk/public_html/wp-includes/general-template.php(48): locate_template(Array, true, true, Array) #12 /home/dmg165pk/public_html/wp-content/plugins/woocommerce/templates/single-product.php(22): get_header('shop') #13 /home/dmg165pk/public_html/wp-includes/template-loader.php(106): include('/home/dmg165pk/...') #14 /home/dmg165pk/public_html/wp-blog-header.php(19): require_once('/home/dmg165pk/...') #15 /home/dmg165pk/public_html/index.php(17): require('/home/dmg165pk/...') #16 {main} thrown in /home/dmg165pk/public_html/wp-content/themes/storefront-child/functions.php on line 740