Как визуализировать дерево решений в Python

import graphviz
# DOT data
dot_data = tree.export_graphviz(clf, out_file=None, 
                                feature_names=iris.feature_names,  
                                class_names=iris.target_names,
                                filled=True)

# Draw graph
graph = graphviz.Source(dot_data, format="png") 
graph
pythonized