$this->sort = function ($a, $b) {
return $a->getMTime() - $b->getMTime();
};
- } elseif (is_callable($sort)) {
+ } elseif (\is_callable($sort)) {
$this->sort = $sort;
} else {
throw new \InvalidArgumentException('The SortableIterator takes a PHP callable or a valid built-in sort algorithm as an argument.');