private CndImporter importNodesFromCND( InputStream cndInputStream ) throws IOException {
Problems problemsDuringImport = new SimpleProblems();
CndImporter cndImporter = new CndImporter(new ExecutionContext());
cndImporter.importFrom(cndInputStream, problemsDuringImport, null);
if (problemsDuringImport.hasErrors()) {
problemsDuringImport.writeTo(LOGGER);
return null;
}