Nvd\Crud\Form::__call PHP Method

    public function __call($attr, $args = null)
    {
        if (!property_exists($this, $attr)) {
            throw new \Exception("Method {$attr} does not exist.");
        }
        if (count($args)) {
            $this->{$attr} = $args[0];
            return $this;
        }
        return $this->{$attr};
    }