code: def test_add_mean_shift_to_first_layer(load_mnist_model):
      model = PyTorchModel(load_mnist_model, channel_first=True)
      shift = -1
      arr = np.random.random((32, 1, 28, 28))
      X = torch.Tensor(arr).to(model.device)
  
      X_shift = torch.Tensor(arr + shift).to(model.device)
      new_model = model.add_mean_shift_to_first_layer(shift, X.size())
      a1 = model.model(X)
      a2 = new_model(X_shift)
      assert torch.all(torch.isclose(a1, a2, atol=1e-04))
  
file_path: Quantus/tests/functions/test_pytorch_model.py
imports: from collections import OrderedDict
  from typing import Union
  import numpy
  import pytest
  import torch
  from pytest_lazyfixture import lazy_fixture
  from scipy.special import softmax
  from quantus.helpers.model.pytorch_model import PyTorchModel
label_desc: Use image node_id 9 for calling a global function with example usage: test_add_mean_shift_to_first_layer(load_mnist_model) without return types