protected Automaton createEmptyAutomaton(Document document) {
		Map e2t = elementsToText(document.getDocumentElement());
		String s = (String) e2t.get(TURING_TAPES_NAME);
		if (s == null)
			s = "1";
		try {
			int tapes = Integer.parseInt(s);
			if (tapes < 1 || tapes > 5)
				throw new DataException(tapes
						+ " invalid # of tapes.  Valid # of tapes 1-5.");
			return new TuringMachine(tapes);
		} catch (NumberFormatException e) {
			throw new DataException("Error reading " + s
					+ " as number of tapes.");
		}
	}