this.usedVariables = new TreeSet<String>();
final Engine engine = new Engine();
final ScopedMap scopedMap = new ScopedMap(Collections.EMPTY_MAP);
ProcessListener processListener = new ProcessListener() {
@Override
public void log(TemplateContext context, Token token, Action action) {
if (token instanceof ExpressionToken) {
String variable = ((ExpressionToken) token).getExpression();