public function getRequiredFields()
    {
        // Generate required field validator
        $requiredNames = $this
            ->getController()
            ->data()
            ->Fields()
            ->filter('Required', true)
            ->column('Name');
        $requiredNames = array_merge($requiredNames, $this->getEmailRecipientRequiredFields());
        $required = new RequiredFields($requiredNames);
        $this->extend('updateRequiredFields', $required);
        $required->setForm($this);
        return $required;
    }