@Override
public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException {
try {
Debuggee dbgr = BrokerPool.getInstance().getDebuggee();
IoSession session = (IoSession) dbgr.getSession(args[0].getStringValue());
if (session == null) return BooleanValue.FALSE;
Command command = new org.exist.debuggee.dbgp.packets.StepInto(session, "");
command.exec();