How to Hide Revi.io - Customer and Product Reviews Admin Menus

function plt_hide_revi_io_customer_and_product_reviews_menus() {
	//Hide the "Revi" menu.
	remove_menu_page('revi');
}

add_action('admin_menu', 'plt_hide_revi_io_customer_and_product_reviews_menus', 11);

Where do I put this code?