# 0.5.1 - 2020-03-29¶

## compose¶

• compose.Pipeline and compose.TransformerUnion now variadic arguments as input instead of a list. This doesn't change anything when using the shorthand operators | and +.

## model_selection¶

• Removed model_selection.successive_halving
• Added model_selection.SuccessiveHalvingRegressor and model_selection.SuccessiveHalvingClassifier

## stream¶

• Added a copy parameter to stream.simulate_qa in order to handle unwanted feature modifications.

## tree¶

• Added a curtail_under parameter to tree.DecisionTreeClassifier.
• The speed and accuracy of both tree.DecisionTreeClassifier and tree.RandomForestClassifier has been slightly improved for numerical attributes.
• The esthetics of the tree.DecisionTreeClassifier.draw method have been improved.