code: def test_handle_binary_classifier(mocker, model):
      backprop = Backprop(model)
  
      target_class = 0
      input_ = torch.zeros([1, 3, 224, 224])
  
      mock_output = torch.tensor([0.8])
      mock_output.requires_grad = True
      mocker.patch.object(model, "forward", return_value=mock_output)
  
      backprop.calculate_gradients(input_, target_class)
  
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 9 for calling a global function with example usage: test_handle_binary_classifier(mocker, model) without return types