Nette\Forms\Container::__call PHP Method

    public function __call($name, $args)
    {
        if ($callback = Nette\Utils\ObjectMixin::getExtensionMethod(__CLASS__, $name)) {
            return Nette\Utils\Callback::invoke($callback, $this, ...$args);
        }
        return parent::__call($name, $args);
    }

 /**
  * @param $name
  * @param $args
  * @return \Nette\Forms\Container|Container
  */
 public function __call($name, $args)
 {
     if (substr($name, 0, 3) !== 'add') {
         return parent::__call($name, $args);
     }
     $args = array_merge(array(lcfirst(substr($name, 3))), $args);
     return call_user_func_array(array($this, 'add'), $args);
 }