sample_weight
            Optionally, some sample weights to apply to the target `series` labels.
            They are applied per observation, per label (each step in `output_chunk_length`), and per component.
            If a string, then the weights are generated using built-in weighting functions. The available options are
            `"linear_decay"` or `"exponential_decay"`. The weights are only computed the longest series in `series`,
            and then applied globally to all `series` to have a common time weighting.
            If a `TimeSeries` or `Sequence[TimeSeries]`, then those weights are used. The number of series must
            match the number of target `series` and each series must contain at least all time steps from the
            corresponding target `series`. If the weight series only have a single component / column, then the weights
            are applied globally to all components in `series`. Otherwise, for component-specific weights, the number
            of components must match those of `series`.
val_sample_weight
            Same as for `sample_weight` but for the evaluation dataset.