Php 如何在设置上创建optgroup

你们知道如何在woocommerce设置中创建opt组吗？我已经创建了它，但并没有在woocommerce设置中显示

'provinsi'    => array(
                    'name'    => __( 'Provinsi', 'woocommerce-settings-tab-cekongkir' ),
                    'type'    => 'select',
                    'optgroup'=> array(
                        '1'=>'ridwan'),//opt group
                    'options' => array(
                        '1'  => 'Bali',
                        '2'  => 'Bangka Belitung',
                        '3'  => 'Banten',
                        '4'  => 'Bengkulu',
                        '5'  => 'DI Yogyakarta',
                        '6'  => 'DKI Jakarta',
                        '7'  => 'Gorontalo',
                        '8'  => 'Jambi',),
                    'desc_tip'   => true,
                    'id'     => 'wc_settings_tab_demo_title_section-1',
                    'css' => 'min-width:200px'
                ),

---

请帮我所有的忙。

使用此过滤器时，请使用以下设置

add_filter( 'woocommerce_general_settings', 'provinsi_add_a_setting' );

function provinsi_add_a_setting( $settings ) {

    $settings[] = array( 'name' => __( 'Provinsi Custom Settings', 'textdomain' ), 'type' => 'title', 'desc' => '', 'id' => 'woocommerce_provinsi_settings' );

    $settings[] = array(
        'title'     => __( 'Provinsi', 'textdomain' ),
        'desc'      => '',
        'id'        => 'woocommerce_provinsi_select_field',
        'desc'      => __( 'This is a sample text field added', 'textdomain' ),
        'type'      => 'select',
        'options' => array(
                    '1'  => 'Bali',
                    '2'  => 'Bangka Belitung',
                    '3'  => 'Banten',
                    '4'  => 'Bengkulu',
                    '5'  => 'DI Yogyakarta',
                    '6'  => 'DKI Jakarta',
                    '7'  => 'Gorontalo',
                    '8'  => 'Jambi'
         ),
        'default'   => '',
        'desc_tip'  => false,
        //'placeholder' => __( 'Placeholder Text', 'textdomain' ),
    );

    $settings[] = array( 'type' => 'sectionend', 'id' => 'woocommerce_provinsi_settings');

    return $settings;

}