declare class Menu {
	private constructor();

	/**
	 * Adds an item to the menu. The label for a menu item should be in sentence case (only the first
	 * word capitalized).
	 * 
	 * @param caption - The label for the menu item, with only the first word capitalized.
	 * @param functionName - The name of the function to invoke when the user selects the item. You can
	 *     use functions from included libraries, such as <code>Library.libFunction1</code>.
	 * 
	 * @returns This <code><a target='_blank' href='https://developers.google.com/apps-script/reference/base/menu.html'>Menu</a></code>, for chaining.
	 */
	addItem(
		caption: string,
		functionName: string
	): Menu
	/**
	 * Adds a visual separator to the menu.
	 * 
	 * @returns This <code><a target='_blank' href='https://developers.google.com/apps-script/reference/base/menu.html'>Menu</a></code>, for chaining.
	 */
	addSeparator(): Menu
	/**
	 * Adds a sub-menu to the menu.
	 * 
	 * @param menu - The sub-menu, constructed like a top-level menu.
	 * 
	 * @returns This <code><a target='_blank' href='https://developers.google.com/apps-script/reference/base/menu.html'>Menu</a></code>, for chaining.
	 */
	addSubMenu(
		menu: Menu
	): Menu
	/**
	 * Inserts the menu into the instance of the editor's user interface.
	 */
	addToUi(): void

}