public function setCc($cc)
    {
        if ($cc instanceof Email) {
            $cc = [$cc];
        }

        foreach ($cc as $email) {
            if (!$email instanceof Email) {
                throw new MailerException('Email must be an instance of \Webiny\Component\Mailer\Email.');
            }
            $this->addCc($email);
        }

        return $this;
    }