docstr: Test the mapping function.
docstr_tok: ["Test","the","mapping","function","."]
code: def test_map_nested(self):
      """Test the mapping function."""
  
      def map_fn(x):
          return x * 10
  
      result = py_utils.map_nested(
          map_fn,
          {
              "a": 1,
              "b": {
                  "c": 2,
                  "e": [3, 4, 5],
              },
          },
      )
      self.assertEqual(
          result,
          {
              "a": 10,
              "b": {
                  "c": 20,
                  "e": [30, 40, 50],
              },
          },
      )
  
      result = py_utils.map_nested(map_fn, [1, 2, 3])
      self.assertEqual(result, [10, 20, 30])
  
      result = py_utils.map_nested(map_fn, 1)
      self.assertEqual(result, 10)
  
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 2 for calling the PyUtilsTest obj's underlying member method code with example usage: obj.test_map_nested() and returns: unknown