from tensorflow.contrib.layers.python.layers import feature_column as contrib_feature_column


    classifier = estimator.GradientBoostedDecisionTreeClassifier(
        learner_config=learner_config,
        num_trees=1,
        examples_per_layer=3,
        model_dir=model_dir,
        config=config,
        feature_columns=[contrib_feature_column.real_valued_column("x")])

    classifier.fit(input_fn=_train_input_fn, steps=15)
    classifier.evaluate(input_fn=_eval_input_fn, steps=1)
    classifier.export(self._export_dir_base)

  def testThatLeafIndexIsInPredictions(self):
