How to Hide the "YYDevelopment Accessibility" Admin Menu

function plt_hide_yydevelopment_accessibility_menus() {
	//Hide the "Settings → YYDevelopment Accessibility" menu.
	remove_submenu_page('options-general.php', 'yydev-accessibility');
}

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

Where do I put this code?