使用锚定漫游程序(Walker_Nav_Menu)时出错，在子菜单中插入锚定父项的类

class Custom_Walker_Nav_Menu extends Walker_Nav_Menu {
    function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
        $indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';

        $classes = empty( $item->classes ) ? array() : (array) $item->classes;
        $classes[] = 'menu-item-' . $item->ID;

        // Check if the current item has children
        $has_children = $args->walker->has_children;

        // Add custom class to parent menu item if it has children
        if ( $has_children && $depth === 0 ) {
            $classes[] = 'has-children';
        }

        // Add custom class to child menu items
        if ( $depth > 0 ) {
            $classes[] = 'child-menu-item';
        }

        $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args, $depth ) );
        $class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';

        $output .= $indent . '<li' . $class_names . '>';

        // ... Rest of the code for rendering the menu item

        // Add anchor class to parent menu item
        if ( $has_children && $depth === 0 ) {
            $output .= '<a class="parent-menu-item" href="' . esc_url( $item->url ) . '">' . $title . '</a>';
        } else {
            $output .= '<a href="' . esc_url( $item->url ) . '">' . $title . '</a>';
        }
    }
}

// Replace the default menu walker with custom walker
add_filter( 'wp_nav_menu_args', 'custom_menu_walker' );
function custom_menu_walker( $args ) {
    $args['walker'] = new Custom_Walker_Nav_Menu();
    return $args;
}