public DataNode get(String name) {
   for (DataNode i : getChildren()) {
     if (i.getName().equals(name)) {
       return i;
     }
   }
   return null;
 }
 /**
  * called after modifying the list. It checks that names within the list are unique, and that
  * every item has this item as its parent
  *
  * @param newItem
  */
 private void checkConsistency(DataNode newItem) {
   if (members == null) {
     return; // nothing changed
   }
   Set<String> names = new HashSet<>();
   for (DataNode item : members) {
     if (names.contains(item.getName())) {
       if (newItem != null) {
         throw new RuntimeException(
             "Found duplicate name: "
                 + item.getName()
                 + " when adding item: "
                 + newItem.getName()
                 + " to directory: "
                 + getName());
       } else {
         throw new RuntimeException(
             "Found duplicate name: " + item.getName() + " in parent: " + getName());
       }
     }
     if (item.getParent() != this) {
       throw new RuntimeException(
           "Found item in this set which does not have this item as its parent: "
               + item.getName()
               + ". Its parent is: "
               + item.getParent().getName()
               + " and my name is : "
               + this.getName());
     }
     names.add(item.getName());
   }
 }