I wonder if it is possible to use a MultilabelBinarizer within a ColumnTransformer. I have a toy pandas dataframe like: df = pd.DataFrame({"id":[1,2,3], "text": ["some text", "some other text", "yet another text"], "label": [["white", "cat"], ["black", "cat"], ["brown", "dog"]]}) preprocess = ColumnTransformer( [ ('vectorizer', CountVectorizer(), 'text'), ('binarizer', MultiLabelBinarizer(), ['label']), ], remainder='drop') this code, however, throws an exception: ~/lib/python3.7/site-packages/sklearn/pipeline.py in _fit_transform_one(transformer, X, y, weight, message_clsname, message, **fit_params) 714 with _print_elapsed_time(message_clsname, message): 715 if hasattr(transformer, 'fit_transform'): --> 716 res = transformer.fit_transform(X, y, **fit_params) 717 else: 718 res = transformer.fit(X, y, **fit_params).transform(X) TypeError: fit_transform() takes 2 positional arguments but 3 were given With OneHotEncoder the ColumnTransformer does work. Continue reading...