'Fit OneHotEncoder to X, then transform X.
Equivalent to self.fit(X).transform(X), but more convenient and more
efficient. See fit for the parameters, transform for the return value.
Parameters
X : array-like, shape [n_samples, n_feature]
Input array of type int.'

def fit_transform(self, X, y=None):

    return _transform_selected(X, self._fit_transform, self.categorical_features, copy=True)
