/**
* Decorate $email with categories.
*
* @param EmailInterface $email
*
* @return EmailInterface|EmailDecorator
*/
protected function decorateWithCategories(EmailInterface $email)
{
if (!$email instanceof EmailDecorator) {
$email = new EmailDecorator($email);
}
if (!is_null($this->categories)) {
$email->setCategories($this->categories);
}
return $email;
}
