def _check_fixed_params(self, transformer_selector: Iterable) -> None:
        """
        Raises `ValueError` if `self._parallel_params` specifies a `key` in
        `self._fixed_params` that should be distributed, but
        `len(self._fixed_params[key])` does not equal to the number of time series
        (the maximum value + 1 from `transformer_selector`).
        """
        for key in self._parallel_params:
            n_timeseries_ = max(transformer_selector) + 1
            if n_timeseries_ > len(self._fixed_params[key]):
                raise_log(
                    ValueError(
                        f"{n_timeseries_} TimeSeries were provided "
                        f"but only {len(self._fixed_params[key])} {key} values "
                        f"were specified upon initialising {self.name}."
                    ),
                    logger=logger,
                )
            elif n_timeseries_ < len(self._fixed_params[key]):
                logger.warning(
                    f"Only {n_timeseries_} TimeSeries were provided "
                    f"which is lower than the number of {key} values "
                    f"(n={len(self._fixed_params[key])}) that were specified "
                    f"upon initialising {self.name}."
                )
        return None

        Raises `ValueError` if `self._parallel_params` specifies a `key` in
        `self._fixed_params` that should be distributed, but
        `len(self._fixed_params[key])` does not equal to the number of time series
        (the maximum value + 1 from `transformer_selector`).
        
darts/dataprocessing/transformers/base_data_transformer.py