public function add(FormType $_type, $_options)
{
static $added = array();
$item = FormType::computeItem($_type, $_options);
if (array_key_exists("name", $item)) {
if (isset($added[$item["name"]])) {
throw new \InvalidArgumentException("Name '{$item["name"]}' already exists!");
}
$added[$item["name"]] = true;
}
$item["type"] = $_type;
$this->items[] = $item;
}
