code: def test_nested(self):
      nested_dict = {"a": 1, "b": [2, 3, 4], "c": {"d": 8}}
      self._assert_keys_values(
          tff.utils.iterate_nested(nested_dict),
          expected_keys=["a", "b", "c_d"],
          expected_values=[1, [2, 3, 4], 8],
      )
  
file_path: tf-quant-finance/tf_quant_finance/utils/tf_functions_test.py
imports: from typing import Dict
  import dataclasses
  import tensorflow.compat.v2
  import tf_quant_finance
  from tensorflow.python.framework import test_util
label_desc: Use image node_id 5 for calling the TfFunctionsTest obj's underlying member method code with example usage: obj.test_nested() without return types