code: def test_dict_only(self):
      def map_fn(x):
          return x[0] + x[1]
  
      arg0 = {
          "a": (1, 2),
          "b": {
              "c": 2,
              "e": [3, 4, 5],
          },
      }
      arg1 = {
          "a": (10, 20),
          "b": {
              "c": 20,
              "e": [30, 40, 50],
          },
      }
  
      result = py_utils.zip_nested(arg0, arg1, dict_only=True)
      self.assertEqual(
          result,
          {
              "a": ((1, 2), (10, 20)),
              "b": {
                  "c": (2, 20),
                  "e": ([3, 4, 5], [30, 40, 50]),
              },
          },
      )
  
      result = py_utils.map_nested(map_fn, result, dict_only=True)
      self.assertEqual(
          result,
          {
              "a": (1, 2, 10, 20),
              "b": {
                  "c": 22,
                  "e": [3, 4, 5, 30, 40, 50],
              },
          },
      )
  
imports: import collections
  import pathlib
  from etils import epath
  import pytest
  import tensorflow
  from tensorflow_datasets import testing
  from tensorflow_datasets.core import constants
  from tensorflow_datasets.core import utils
  from tensorflow_datasets.core.utils import py_utils
label_desc: Use image node_id 4 for calling the PyUtilsTest obj's underlying member method code with example usage: obj.test_dict_only() and returns: unknown