code: def test_assert_correct_layer_format_4():
      """[Utils] assert_correct_format: prep - inst, est - inst."""
      assert_correct_format(OLS(), Scale())
  
imports: import numpy
  from mlens.externals.sklearn.base import clone
  from mlens.utils.checks import check_ensemble_build, assert_valid_estimator, assert_correct_format, check_initialized
  from mlens.utils.dummy import OLS, Scale
  from mlens.testing import EstimatorContainer
  from mlens.utils.exceptions import LayerSpecificationError, LayerSpecificationWarning, NotFittedError, ParallelProcessingError, ParallelProcessingWarning
label_desc: Use image node_id 11 for calling a global function with example usage: test_assert_correct_layer_format_4() without return types