title: How to explore a decision tree built using scikit learn
body: <p>I am building a decision tree using </p>
  
  <pre><code>clf = tree.DecisionTreeClassifier()
  clf = clf.fit(X_train, Y_train)
  </code></pre>
  
  <p>This all works fine. However, how do I then explore the decision tree? </p>
  
  <p>For example, how do I find which entries from X_train appear in a particular leaf?</p>