code: def test_custom_task(mnist_train_custom_task, mnist_test_custom_task):
      # Arrange
      check = HeatmapComparison(n_samples=None)
  
      # Act
      result = check.run(
          mnist_train_custom_task, mnist_test_custom_task
      )
  
      # Assert
      brightness_diff = result.value["diff"]
      assert_that(brightness_diff.mean(), close_to(1.095, 0.001))
      assert_that(brightness_diff.max(), close_to(9, 0.001))
  
imports: from hamcrest import assert_that, close_to, greater_than, has_length
  from deepchecks.vision.checks import HeatmapComparison
label_desc: Use image node_id 4 for calling a global function with example usage: test_custom_task(mnist_train_custom_task, mnist_test_custom_task) without return types