Warning: Undefined variable $arr in /mnt/web319/b0/37/54544837/htdocs/app/controllers/products.php on line 63

Fatal error: Uncaught TypeError: array_keys(): Argument #1 ($array) must be of type array, null given in /mnt/web319/b0/37/54544837/htdocs/app/core/model.php:88
Stack trace:
#0 /mnt/web319/b0/37/54544837/htdocs/app/core/model.php(88): array_keys()
#1 /mnt/web319/b0/37/54544837/htdocs/app/controllers/products.php(63): Model->read_first()
#2 /mnt/web319/b0/37/54544837/htdocs/app/core/app.php(85): Products->index()
#3 /mnt/web319/b0/37/54544837/htdocs/public/index.php(17): App->loadController()
#4 {main}
  thrown in /mnt/web319/b0/37/54544837/htdocs/app/core/model.php on line 88