code: def test_forward_pre_hook_self_function_with_input_only(self) -> None:
      class TestModule(LazyModuleExtensionMixin, torch.nn.Module):
          """
          Create this unit test to make sure the old way of initialize self hook function
          is enabled, with the hook definition as:
              valid_input_only_hook(self, module, input)
  
          if we run the TestModule as::
  
              m = TestModule()
              output = m()
              expected_output = torch.zeros(2, 2)
          """
  
          def __init__(self, *args, **kwargs):
              super().__init__(*args, **kwargs)
              self.register_forward_pre_hook(self.valid_input_only_hook)
  
          def valid_input_only_hook(self, module, input):
              self.output = torch.zeros(2, 2)
  
          def initialize_parameters(self) -> None:
              return None
  
          def forward(self) -> torch.Tensor:
              return self.output
  
      m = TestModule()
  
      # test for self function registeration with register_forward_pre_hook
      output_forward = m()
      self.assertTrue(
          torch.allclose(output_forward, torch.zeros(2, 2)),
          "Please make sure forward function is executed as expected.",
      )
  
file_path: torchrec/torchrec/modules/tests/test_lazy_extension.py
imports: import inspect
  import re
  import unittest
  from typing import Tuple
  import torch
  from torch.nn.modules.lazy import LazyModuleMixin
  from torchrec.modules.lazy_extension import lazy_apply, LazyModuleExtensionMixin
label_desc: Use image node_id 3 for calling the TestLazyModuleExtensionMixin obj's underlying member method code with example usage: obj.test_forward_pre_hook_self_function_with_input_only() and returns: None, self