First stage: Fixed SetArtilleriesGeneric

SetArtilleriesGeneric.java

@@ -50,7 +50,7 @@ public class SetArtilleriesGeneric<T> {
         return _places.get(position);
     }
 
-    public Iterator<T> getArtilleries() {
-        return _places.stream().filter(Objects::nonNull).iterator();
+    public Iterable<T> getArtilleries() {
+        return () -> _places.stream().filter(Objects::nonNull).iterator();
     }
 }