code: def add_items(self, data_dict, root=None, target=None):
          
          if root is None:
              print("Warning: TreeCtrl root must be given.")
              return
          if target is None:
              print("Warning: TreeCtrl target must be given.")
              return
          for k in sorted(data_dict):
              if isinstance(data_dict[k], dict):
                  k_item_root = target.AppendItem(root, k)
                  self.add_items(data_dict[k], k_item_root, target)
              else:
                  item_val = ' : '.join((k, str(data_dict[k])))
                  target.AppendItem(root, item_val)
docs: add items for tree
              :param data_dict: dict of tree data
              :param root: treeitemid of tree root
              :param target: treectrl obj