code: def test_traverse_dataclass_attr(self):
      x = Point(x=1, y=2)
      traversal = traverse_util.t_identity.y
      self.assertEqual(list(traversal.iterate(x)), [2])
      y = traversal.update(lambda x: x + x, x)
      self.assertEqual(y, Point(x=1, y=4))
  
imports: import collections
  import jax
  import jax.numpy
  import numpy
  import optax
  from absl.testing import absltest
  import flax
  from flax import traverse_util
  from flax.core import freeze
label_desc: Use image node_id 8 for calling the TraversalTest obj's underlying member method code with example usage: obj.test_traverse_dataclass_attr() without return types