code: def test_dict(self, params, input_data, expected):
      result = FlattenSubKeysd(**params)(input_data)
      self.assertSetEqual(set(result.keys()), set(expected.keys()))
      for k in expected:
          self.assertEqual(id(result[k]), id(expected[k]))
  
file_path: MONAI/tests/test_flatten_sub_keysd.py
imports: from __future__ import annotations
  import unittest
  import torch
  from parameterized import parameterized
  from monai.transforms import FlattenSubKeysd
label_desc: Use image node_id 1 for calling the TestFlattenSubKeysd obj's underlying member method code with example usage: obj.test_dict(params, input_data, expected) without return types