code: @Override
  	public Collection<String> sendEmailMessages(final Collection<EmailMessage> emailMessages)
  		throws MessagingException
  	{
  		final List<String> messageIds = new ArrayList<>();
  		for (final EmailMessage emailMessage : emailMessages)
  		{
  			final String messageId = sendEmailMessage(emailMessage);
  			messageIds.add(messageId);
  		}
  		return messageIds;
  	}
docs: {@inheritDoc}