code: def test_register_hook_to_first_conv_layer(
      mocker, name, model_module
  ):
      model = model_module()
  
      conv_layer = find_first_conv_layer(
          model, nn.modules.conv.Conv2d, 3
      )
      mocker.spy(conv_layer, "register_backward_hook")
  
      Backprop(model)
  
      conv_layer.register_backward_hook.assert_called_once()
  
imports: import inspect
  import pytest
  import torch
  import torch.nn
  import torch.nn.functional
  import torchvision.models
  from flashtorch.saliency import Backprop
label_desc: Use image node_id 19 for calling a global function with example usage: test_register_hook_to_first_conv_layer(mocker, name, model_module) without return types