def generate_inference_idx(
        self, n: int, target: TimeSeries, covariates: Optional[TimeSeries] = None
    ) -> tuple[SupportedIndex, pd.Timestamp]:
        """
        Generates/extracts time index (or integer index) for covariates at model inference / prediction time.

        Parameters
        ----------
        n
            The forecasting horizon.
        target
            The target TimeSeries used during training or passed to prediction as `series`.
        covariates
            Optionally, the covariates used for prediction.
            If given, the returned time index is equal to the `covariates` time index. Else, the returned time index
            covers the minimum required covariate time spans for performing inference / prediction with a specific
            forecasting model. These requirements are derived from parameters set at :class:`CovariatesIndexGenerator`
            creation.
        """
        pass

        Generates/extracts time index (or integer index) for covariates at model inference / prediction time.

        Parameters
        ----------
        n
            The forecasting horizon.
        target
            The target TimeSeries used during training or passed to prediction as `series`.
        covariates
            Optionally, the covariates used for prediction.
            If given, the returned time index is equal to the `covariates` time index. Else, the returned time index
            covers the minimum required covariate time spans for performing inference / prediction with a specific
            forecasting model. These requirements are derived from parameters set at :class:`CovariatesIndexGenerator`
            creation.
        
darts/dataprocessing/encoders/encoder_base.py