How to Hide Widget Data - Setting Import/Export Plugin Admin Menus

function plt_hide_widget_settings_importexport_menus() {
	//Hide the "Tools → Widget Settings Import" menu.
	remove_submenu_page('tools.php', 'widget-settings-import');
	//Hide the "Tools → Widget Settings Export" menu.
	remove_submenu_page('tools.php', 'widget-settings-export');
}

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

Where do I put this code?