docstr: Instantiates a Corpus for text classification from CSV column formatted data.
  
  :param data_folder: base folder with the task data
  :param train_file: the name of the train file
  :param test_file: the name of the test file
  :param dev_file: the name of the dev file, if None, dev data is sampled from train
  :return: a Corpus with annotated train, dev and test data
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code: def __init__(
      self,
      source_file: Union[str, Path],
      target_file: Union[str, Path],
      name: str,
      use_tokenizer: bool = True,
      max_tokens_per_doc=-1,
      max_chars_per_doc=-1,
      in_memory: bool = True,
      **corpusargs,
  ) -> None:
      """Instantiates a Corpus for text classification from CSV column formatted data.
  
      :param data_folder: base folder with the task data
      :param train_file: the name of the train file
      :param test_file: the name of the test file
      :param dev_file: the name of the dev file, if None, dev data is sampled from train
      :return: a Corpus with annotated train, dev and test data
      """
      train: FlairDataset = ParallelTextDataset(
          source_file,
          target_file,
          use_tokenizer=use_tokenizer,
          max_tokens_per_doc=max_tokens_per_doc,
          max_chars_per_doc=max_chars_per_doc,
          in_memory=in_memory,
      )
  
      self.in_memory = in_memory
  
      super().__init__(train, name=name, **corpusargs)
  
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 1 to create a new ParallelTextCorpus object from inherited base classes: Corpus with example: obj = ParallelTextCorpus(source_file, target_file, name, use_tokenizer, max_tokens_per_doc, max_chars_per_doc, in_memory)