code: def test_apply_update_root_node_unmodified(self):
      def update_fn(path, value):
          if isinstance(value, list):
              value = value.copy()
              value.append(-1)
          return value
  
      l = [[1, 2], [3, 4], 5]
      l2 = cursor(l).apply_update(update_fn).build()
      self.assertEqual(l2, [[1, 2, -1], [3, 4, -1], 5])
  
imports: import dataclasses
  from typing import Any, NamedTuple
  import jax
  import jax.numpy
  import optax
  from absl.testing import absltest
  import flax
  import flax.linen
  from flax.core import freeze
  from flax.cursor import AccessType, _traverse_tree, cursor
  from flax.errors import CursorFindError, TraverseTreeError
  from flax.training import train_state
label_desc: Use image node_id 7 for calling the CursorTest obj's underlying member method code with example usage: obj.test_apply_update_root_node_unmodified() and returns: value