@Override
 public Throwable execute(Scope scope, PrintStream out)
     throws InvocationTargetException, IllegalArgumentException, IllegalAccessException,
         InstantiationException {
   if (!isStaticField) {
     Object receiver = scope.getObject(parameters.get(1));
     if (receiver == null) return new CodeUnderTestException(new NullPointerException());
   }
   return super.execute(scope, out);
 }