code: def _test_functional_optim_registration(self):
      fn_map_key = "MyDummyFnOptimizer"
      fn_optim = MyDummyFnOptimizer
      register_functional_optim(fn_map_key, fn_optim)
      functional_optim_cls = functional_optim_map.get(fn_map_key, None)
      if not functional_optim_cls:
          raise ValueError(
              f"Functional optimizer not registered for {fn_map_key}"
          )
  
imports: from typing import List, Optional, Tuple
  import unittest
  import torch
  import torch.distributed
  import torch.nn
  import torch.nn.functional
  from torch import Tensor
  from torch.optim import SGD, Adam, AdamW
  from torch.testing._internal.common_utils import TestCase, run_tests
label_desc: Use image node_id 3 for calling the TestFunctionalOptimParity obj's underlying member method code with example usage: obj._test_functional_optim_registration() without return types