code: def test_traverse_each_dict(self):
      x = {"foo": 1, "bar": 2}
      traversal = traverse_util.t_identity.each()
      self.assertEqual(list(traversal.iterate(x)), [1, 2])
      y = traversal.update(lambda x: x + x, x)
      self.assertEqual(y, {"foo": 2, "bar": 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 11 for calling the TraversalTest obj's underlying member method code with example usage: obj.test_traverse_each_dict() without return types