def print_statistics(self):
        """
        Print some statistics on the corpus. Only the master process.
        """
        if not self.params.is_master:
            return
        logger.info(f"{len(self)} sequences")
        # data_len = sum(self.lengths)
        # nb_unique_tokens = len(Counter(list(chain(*self.token_ids))))
        # logger.info(f'{data_len} tokens ({nb_unique_tokens} unique)')

        # unk_idx = self.params.special_tok_ids['unk_token']
        # nb_unknown = sum([(t==unk_idx).sum() for t in self.token_ids])
        # logger.info(f'{nb_unknown} unknown tokens (covering {100*nb_unknown/data_len:.2f}% of the data)')

        Print some statistics on the corpus. Only the master process.
        
dpkd/transformers/examples/research_projects/distillation/lm_seqs_dataset.py