How to Hide CSV to HTML Admin Menus

function plt_hide_csv_to_html_menus() {
	//Hide the "CSV to HTML" menu.
	remove_menu_page('csv-to-html');
	//Hide the "CSV to HTML → Shortcode Generator" menu.
	remove_submenu_page('csv-to-html', 'csv-to-html');
	//Hide the "CSV to HTML → Reference List" menu.
	remove_submenu_page('csv-to-html', 'csv-to-html-referencelist');
}

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

Where do I put this code?