public void dele(IoSession session, PopSession popSession, String[] args) {
String sNum = args[1];
int num = Integer.parseInt(sNum);
Message mid = get(popSession, num);
if (mid != null) {
mid.markForDeletion();
popSession.reply(session, "+OK");
return;
} else {
popSession.reply(session, "-ERR no such message");
}