How to Hide the "Accessibility Toolbar" Admin Menu

function plt_hide_ity_accessibility_toolbar_menus() {
	//Hide the "Settings → Accessibility Toolbar" menu.
	remove_submenu_page('options-general.php', 'ityacto-accessibility-toolbar');
}

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

Where do I put this code?