Polyfills that call `array_keys()`, `array_values()` or `range()` are inefficient because they create new arrays unnecessarily.Please use this polyfill instead which creates no new arrays and only does a single pass over the given array.<?phpif (!function_exists("array_is_list")) { function array_is_list(array $array): bool { $i = 0; foreach ($array as $k => $v) { if ($k !== $i++) { return false; } } return true; }}?>