Fixed method visibility

src/main/java/org/gcube/informationsystem/knowledge/ModelKnowledge.java

@@ -51,7 +51,7 @@ public class ModelKnowledge<T, NI extends NodeInformation<T>> {
 		reset();
 	}
 	
-	private void reset() {
+	protected void reset() {
 		
 		this.trees = new HashMap<>();
 		this.erTypesUsage = new HashMap<>();