public MailMessage[] GetMessages(IEmailMessage emailMessage)
        {
            if (emailMessage is ProductQuestionMessage)
            {
                return(GetProductQuestionTypeofMessages(emailMessage));
            }

            if (emailMessage is NewsletterMessage)
            {
                return(GetNewsletterTypeofMessages(emailMessage));
            }

            throw new UnknownEmailMessageType(emailMessage.GetType());
        }