如何以编程方式将照片从具有多个文件输入的前端添加到cmb2元字段类型file_list

function my_custom_metabox() {
    $cmb = new_cmb2_box( array(
        'id'           => 'my_metabox',
        'title'        => 'My Metabox',
        'object_types' => array( 'post' ), // 可以根据需要更改对象类型
    ) );

    $cmb->add_field( array(
        'name' => 'Photos',
        'id'   => 'my_photos',
        'type' => 'file_list',
    ) );
}
add_action( 'cmb2_admin_init', 'my_custom_metabox' );

<form method="post" enctype="multipart/form-data">
    <input type="file" name="my_photos[]" multiple>
    <input type="submit" value="Upload">
</form>

if ( isset( $_FILES['my_photos'] ) ) {
    $files = $_FILES['my_photos'];

    foreach ( $files['name'] as $key => $name ) {
        if ( $files['error'][$key] == 0 ) {
            $file = array(
                'name'     => $name,
                'type'     => $files['type'][$key],
                'tmp_name' => $files['tmp_name'][$key],
                'error'    => $files['error'][$key],
                'size'     => $files['size'][$key],
            );

            $upload = wp_handle_upload( $file, array( 'test_form' => false ) );

            if ( isset( $upload['url'] ) ) {
                $photo_url = $upload['url'];

                // 将文件URL添加到cmb2元字段
                $photos = get_post_meta( get_the_ID(), 'my_photos', true );
                $photos[] = $photo_url;
                update_post_meta( get_the_ID(), 'my_photos', $photos );
            }
        }
    }
}