Fatal error: Uncaught TypeError: usort(): Argument #2 ($callback) must be a valid callback, function "sortCategories" not found or invalid function name in /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-content/themes/nolabel/template-parts/page/content-category.php:3 Stack trace: #0 /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-content/themes/nolabel/template-parts/page/content-category.php(3): usort(Array, 'sortCategories') #1 /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-includes/template.php(812): require('/home/klient.dh...') #2 /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-includes/template.php(745): load_template('/home/klient.dh...', false, Array) #3 /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-includes/general-template.php(206): locate_template(Array, true, false, Array) #4 /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-content/themes/nolabel/category.php(9): get_template_part('template-parts/...', 'category') #5 /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-includes/template-loader.php(106): include('/home/klient.dh...') #6 /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-blog-header.php(19): require_once('/home/klient.dh...') #7 /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/index.php(17): require('/home/klient.dh...') #8 {main} thrown in /home/klient.dhosting.pl/nolabelvfx/nolabel.pl/public_html/wp-content/themes/nolabel/template-parts/page/content-category.php on line 3