code: def test_one_level_nested(self):
      ori_in = OrderedDict({"a": {"b": 1}, "c": {"d": 2}, "e": 3})
      in_ = copy.deepcopy(ori_in)
      result = flatten_dict(in_)
      assert in_ == ori_in
      assert result == {"a/b": 1, "c/d": 2, "e": 3}
  
imports: import copy
  from collections import OrderedDict
  import pytest
  import sys
  import unittest
  from unittest.mock import patch
  from ray.tune.utils.util import wait_for_gpu
  from ray.tune.utils.util import flatten_dict, unflatten_dict, unflatten_list_dict
label_desc: Use image node_id 2 for calling the FlattenDictTest obj's underlying member method code with example usage: obj.test_one_level_nested() without return types