diff --git a/treetensor/common/object.py b/treetensor/common/object.py
index a493a7ef243ae90c33a808a5e968558e96933a5a..c089cc52d73cbd702c350525b28e3618b3e12746 100644
--- a/treetensor/common/object.py
+++ b/treetensor/common/object.py
@@ -37,7 +37,7 @@ class Object(BaseTreeStruct, metaclass=clsmeta(_object, allow_dict=True)):
             └── x --> <Object 0x7fe00b115ee0>
                 └── c --> 233
         """
-        super(BaseTreeStruct, self).__init__(data)
+        BaseTreeStruct.__init__(self, data)
 
     @ireduce(builtins.all, piter=list)
     @method_treelize()
diff --git a/treetensor/common/trees.py b/treetensor/common/trees.py
index 6fa56ad1266d689ee3796c46137d5e67be67c8cd..f96ebe385ea6011e8e8609dcbeac5c54ac564940 100644
--- a/treetensor/common/trees.py
+++ b/treetensor/common/trees.py
@@ -8,7 +8,6 @@ from typing import Type
 from treevalue import func_treelize as original_func_treelize
 from treevalue import general_tree_value, TreeValue, typetrans
 from treevalue.tree.common import TreeStorage
-from treevalue.tree.tree.tree import get_data_property
 from treevalue.utils import post_process
 
 from ..utils import replaceable_partial, args_mapping
@@ -49,7 +48,7 @@ def print_tree(tree: TreeValue, repr_: Callable = str,
 
         _need_iter = True
         if isinstance(node, TreeValue):
-            _node_id = id(get_data_property(node))
+            _node_id = id(node._detach())
             if show_node_id:
                 _content = f'<{node.__class__.__name__} {hex(_node_id)}>'
             else: