def fit_transform(self, data_inputs, expected_outputs=None):
     FitTransformCallbackStep.fit_transform(self, data_inputs, expected_outputs)
     return self, np.log(data_inputs)
    def fit_transform(self, data_inputs, expected_outputs=None):
        FitTransformCallbackStep.fit_transform(self, data_inputs,
                                               expected_outputs)

        return self, list(np.array(data_inputs) * 2)