code: def _make_bi_sentence(self, source_line: str, target_line: str):
      source_sentence = Sentence(
          source_line, use_tokenizer=self.use_tokenizer
      )
      target_sentence = Sentence(
          target_line, use_tokenizer=self.use_tokenizer
      )
  
      if self.max_tokens_per_doc > 0:
          source_sentence.tokens = source_sentence.tokens[
              : self.max_tokens_per_doc
          ]
          target_sentence.tokens = target_sentence.tokens[
              : self.max_tokens_per_doc
          ]
  
      return TextPair(source_sentence, target_sentence)
  
imports: import logging
  import os
  from pathlib import Path
  from typing import List, Optional, Union
  import flair
  from flair.data import Corpus, DataPair, FlairDataset, Sentence, TextPair, _iter_dataset
  from flair.datasets.base import find_train_dev_test_files
  from flair.file_utils import cached_path, unpack_file, unzip_file
label_desc: Use image node_id 2 for calling the ParallelTextDataset obj's underlying member method code with example usage: obj._make_bi_sentence(source_line, target_line) and returns: TextPair