Computes l2-penalized logistic regression score.
        Parameters
        ----------
        category : str
            category name to score

        category : str
            category name to score
        Returns
        -------
            (coefficient array, accuracy, majority class baseline accuracy)

def get_logistic_regression_coefs_l2(self, category,
                                         clf=RidgeClassifierCV()):
        ''' Computes l2-penalized logistic regression score.
        Parameters
        ----------
        category : str
            category name to score

        category : str
            category name to score
        Returns
        -------
            (coefficient array, accuracy, majority class baseline accuracy)
        '''
        try:
            from sklearn.cross_validation import cross_val_predict
        except:
            from sklearn.model_selection import cross_val_predict
        y = self._get_mask_from_category(category)
        X = TfidfTransformer().fit_transform(self._X)
        clf.fit(X, y)
        y_hat = cross_val_predict(clf, X, y)
        acc, baseline = self._get_accuracy_and_baseline_accuracy(y, y_hat)
        return clf.coef_[0], acc, baseline