FIX: functional contains in internal node

src/mhtree/InternalNode.java

@@ -51,10 +51,6 @@ public class InternalNode extends Node implements Serializable {
     }
 
     public boolean contains(LocalAbstractObject object) {
-        for (Node child : children)
-            if (child.contains(object))
-                return true;
-
-        return false;
+        return children.stream().anyMatch(child -> child.contains(object));
     }
 }