code: def test_path_aware_map_with_empty_nodes(self):
      params_in = {"a": {"b": 10, "c": 2}, "b": {}}
      params_out = traverse_util.path_aware_map(
          lambda path, x: x + 1 if "b" in path else -x, params_in
      )
  
      self.assertEqual(params_out, {"a": {"b": 11, "c": -2}, "b": {}})
  
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 6 for calling the ModelParamTraversalTest obj's underlying member method code with example usage: obj.test_path_aware_map_with_empty_nodes() without return types