def METHOD_NAME(classifier_pipeline_kernel_explainer):
    assert isinstance(classifier_pipeline_kernel_explainer.pdp_df("age"), pd.DataFrame)
    assert isinstance(classifier_pipeline_kernel_explainer.pdp_df("sex"), pd.DataFrame)
    assert isinstance(classifier_pipeline_kernel_explainer.pdp_df("age", index=0), pd.DataFrame)
    assert isinstance(classifier_pipeline_kernel_explainer.pdp_df("sex", index=0), pd.DataFrame)