def METHOD_NAME(self, batch, batch_idx: int):  # type: ignore
    """
    Execute validation step.
    """
    val_loss = self.model.loss(
        **select(self.inputs, batch),
        future_observed_values=batch["future_observed_values"],
        future_target=batch["future_target"],
        loss=self.loss,
    ).mean()
    self.log(
        "val_loss", val_loss, on_epoch=True, on_step=False, prog_bar=True
    )
    return val_loss