def load_dataset(self, split, epoch=1, combine=False, **kwargs):
        """Load a given dataset split.

        Args:
            split (str): name of the split (e.g., train, valid, test)
        """
        paths = utils.split_paths(self.args.data)
        assert len(paths) > 0
        data_path = paths[(epoch - 1) % len(paths)]

        # infer langcode
        src, tgt = self.args.source_lang, self.args.target_lang

        self.datasets[split] = load_langpair_dataset(
            data_path,
            split,
            src,
            self.src_dict,
            tgt,
            self.tgt_dict,
            combine=combine,
            dataset_impl=self.args.dataset_impl,
            upsample_primary=self.args.upsample_primary,
            left_pad_source=self.args.left_pad_source,
            left_pad_target=self.args.left_pad_target,
            max_source_positions=getattr(self.args, "max_source_positions", 1024),
            max_target_positions=getattr(self.args, "max_target_positions", 1024),
            load_alignments=self.args.load_alignments,
            prepend_bos=getattr(self.args, "prepend_bos", False),
            append_source_id=True,
        )
Load a given dataset split.

        Args:
            split (str): name of the split (e.g., train, valid, test)
        
understand_icl/fairseq/fairseq/tasks/translation_from_pretrained_bart.py