Array_slice()在嵌套数组上不能按预期工作

function nestedArraySlice($array, $offset, $length = null) {
    foreach ($array as &$value) {
        if (is_array($value)) {
            $value = nestedArraySlice($value, $offset, $length);
        }
    }
    unset($value);
    
    return array_slice($array, $offset, $length);
}

// 示例嵌套数组
$array = [
    'a' => [
        'b' => [1, 2, 3],
        'c' => [4, 5, 6],
    ],
    'd' => [
        'e' => [7, 8, 9],
        'f' => [10, 11, 12],
    ],
];

// 在嵌套数组上使用Array_slice()
$result = nestedArraySlice($array, 1, 2);

print_r($result);