code: public static MimeMessage emailToMimeMessage(@Nonnull final Email email, @Nonnull final Session session) {
  		try {
  			return MimeMessageProducerHelper.produceMimeMessage(checkNonEmptyArgument(email, "email"), checkNonEmptyArgument(session, "session"));
  		} catch (UnsupportedEncodingException | MessagingException e) {
  			// this should never happen, so we don't acknowledge this exception (and simply bubble up)
  			throw new AssertionError(e.getMessage(), e);
  		}
  	}
docs: Refer to {@link MimeMessageProducerHelper#produceMimeMessage(Email, Session)}