WP_Navigation_Fallback::create_classic_menu_fallback(): int|WP_Error

139	private static function create_classic_menu_fallback() {140		// See if we have a classic menu.141		$classic_nav_menu = static::get_fallback_classic_menu();142 143		if ( ! $classic_nav_menu ) {144			return new WP_Error( 'no_classic_menus', __( 'No Classic Menus found.' ) );145		}146 147		// If there is a classic menu then convert it to blocks.148		$classic_nav_menu_blocks = WP_Classic_To_Block_Menu_Converter::convert( $classic_nav_menu );149 150		if ( is_wp_error( $classic_nav_menu_blocks ) ) {151			return $classic_nav_menu_blocks;152		}153 154		if ( empty( $classic_nav_menu_blocks ) ) {155			return new WP_Error( 'cannot_convert_classic_menu', __( 'Unable to convert Classic Menu to blocks.' ) );156		}157 158		// Create a new navigation menu from the classic menu.159		$classic_menu_fallback = wp_insert_post(160			array(161				'post_content' => $classic_nav_menu_blocks,162				'post_title'   => $classic_nav_menu->name,163				'post_name'    => $classic_nav_menu->slug,164				'post_status'  => 'publish',165				'post_type'    => 'wp_navigation',166			),167			true // So that we can check whether the result is an error.168		);169 170		return $classic_menu_fallback;171	}