Update CNNArch2Caffe2.java

src/main/java/de/monticore/lang/monticar/cnnarch/caffe2generator/CNNArch2Caffe2.java

@@ -51,6 +51,7 @@ public class CNNArch2Caffe2 implements CNNArchGenerator{
     private boolean isSupportedLayer(ArchitectureElementSymbol element, LayerSupportChecker layerChecker){
         List<ArchitectureElementSymbol> constructLayerElemList;
 
+        //first part of if condition ensures that element is not an IOSymbol
         if (element instanceof LayerSymbol && (element.getResolvedThis().get() instanceof CompositeElementSymbol)) {
             constructLayerElemList = ((CompositeElementSymbol)element.getResolvedThis().get()).getElements();
             for (ArchitectureElementSymbol constructedLayerElement : constructLayerElemList) {