code: def test_bootstrap_transformers_panel_format(
      transformer_class, return_actual, expected_index
  ):
      """Tests that the final panel has the right index."""
      transformer = transformer_class(
          n_series=2, return_actual=return_actual
      )
      y_hat = transformer.fit_transform(y)
      assert expected_index.equals(y_hat.index) and (
          y_hat.columns[0] == y.name
      )
  
file_path: sktime/sktime/transformations/bootstrap/tests/test_mbb.py
imports: import pandas
  import pytest
  from sktime.datasets import load_airline
  from sktime.transformations.bootstrap import MovingBlockBootstrapTransformer, STLBootstrapTransformer
  from sktime.transformations.bootstrap._mbb import _get_series_name, _moving_block_bootstrap
  from sktime.utils.validation._dependencies import _check_soft_dependencies
label_desc: Use image node_id 4 for calling a global function with example usage: test_bootstrap_transformers_panel_format(transformer_class, return_actual, expected_index) without return types