code: def test_transforms_only_y():
      """Assert that the pipeline can transform the target column only."""
      data = get_data("bank", verbose=False)
      pc = pycaret.classification.setup(
          data=data,
          preprocess=False,
          custom_pipeline=("label_encoder", LabelEncoder()),
      )
      y = pc.pipeline.fit_transform(y=data.iloc[:, -1])
      assert isinstance(y, pd.Series)
  
file_path: pycaret/tests/test_pipeline.py
imports: import pandas
  import pytest
  from sklearn.preprocessing import LabelEncoder
  import pycaret.classification
  import pycaret.regression
  from pycaret.datasets import get_data
label_desc: Use image node_id 3 for calling a global function with example usage: test_transforms_only_y() without return types