code: def test_add_steps_name_conflict():
      exponent = ExponentTransformer()
      pipe = Pipeline()
      pipe = pipe.add_step(exponent, "exponent", {"X": "X"})
      expected_message = (
          "You try to add a step with a name 'exponent' to the pipeline "
          "that already exists. Try to use an other name."
      )
      pipe = pipe.add_step(exponent, "exponent", {"X": "X"})
      with pytest.raises(ValueError, match=expected_message):
          pipe.fit(MagicMock(), MagicMock())
  
file_path: sktime/sktime/pipeline/tests/test_pipeline.py
imports: from unittest.mock import MagicMock
  import pytest
  from sktime.classification.distance_based import KNeighborsTimeSeriesClassifier
  from sktime.datasets import load_longley
  from sktime.pipeline.pipeline import MethodNotImplementedError, Pipeline
  from sktime.transformations.series.boxcox import BoxCoxTransformer
  from sktime.transformations.series.exponent import ExponentTransformer
label_desc: Use image node_id 2 for calling a global function with example usage: test_add_steps_name_conflict() without return types