examples/research_projects/seq2seq-distillation/utils.py/Seq2SeqDataCollator/_encode
class Seq2SeqDataCollator:    def _encode(self, batch) -> Dict[str, torch.Tensor]:
        batch_encoding = self.tokenizer.prepare_seq2seq_batch(
            [x["src_texts"] for x in batch],
            tgt_texts=[x["tgt_texts"] for x in batch],
            max_length=self.data_args.max_source_length,
            max_target_length=self.data_args.max_target_length,
            padding="max_length" if self.tpu_num_cores is not None else "longest",  # TPU hack
            return_tensors="pt",
            **self.dataset_kwargs,
        )
        return batch_encoding.data