def fit_transform(self, X, y=None):
        return _transform_selected(X, self._fit_transform,
                                   self.categorical_features, copy=True)
When a L{Deferred} encounters a result which is another L{Deferred}
dataset/ETHPy150Open scikit-learn/scikit-learn/sklearn/preprocessing/data.py/OneHotEncoder.fit_transform--crossover with--dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/test/test_defer.py/DeferredTestCase.test_innerCallbacksPreserved