def __init__(self, global_fit: bool):
            """
            Subtracts off the time-averaged mean of each component in a `TimeSeries`.

            If `global_fit` is `True`, then all of the `TimeSeries` provided to `fit` are
            used to compute a single time-averaged mean that will be subtracted from
            every `TimeSeries` subsequently provided to `transform`.

            Conversely, if `global_fit` is `False`, then the time-averaged mean of each
            `TimeSeries` pass to `fit` is individually computed, resulting in `n` means
            being computed if `n` `TimeSeries` were passed to `fit`. If multiple `TimeSeries`
            are subsequently passed to `transform`, the `i`th computed mean will be subtracted
            from the `i`th provided `TimeSeries`.

            Parameters
            ----------
            global_fit
                Whether global fitting should be performed.
            """
            super().__init__(
                name="DataTransformerMock", global_fit=global_fit, mask_components=True
            )

            Subtracts off the time-averaged mean of each component in a `TimeSeries`.

            If `global_fit` is `True`, then all of the `TimeSeries` provided to `fit` are
            used to compute a single time-averaged mean that will be subtracted from
            every `TimeSeries` subsequently provided to `transform`.

            Conversely, if `global_fit` is `False`, then the time-averaged mean of each
            `TimeSeries` pass to `fit` is individually computed, resulting in `n` means
            being computed if `n` `TimeSeries` were passed to `fit`. If multiple `TimeSeries`
            are subsequently passed to `transform`, the `i`th computed mean will be subtracted
            from the `i`th provided `TimeSeries`.

            Parameters
            ----------
            global_fit
                Whether global fitting should be performed.
            
darts/tests/dataprocessing/transformers/test_fittable_data_transformer.py