docstr: 3 reserved keys: 'train', 'val' (optional), 'test'. Represent the split of dataset.
docstr_tok: ["3","reserved","keys",":","'train","'",",","'val","'","(","optional",")",",","'test","'",".","Represent","the","split","of","dataset","."]
code: def raw_file_names(self):
      """3 reserved keys: 'train', 'val' (optional), 'test'. Represent the split of dataset."""
      return {
          "train": "eng.train",
          "test": "eng.testa",
          "val": "eng.testb",
      }
  
imports: from copy import deepcopy
  import stanfordcorenlp
  import torch
  from graph4nlp.pytorch.data.data import GraphData
  from graph4nlp.pytorch.data.dataset import SequenceLabelingDataset
  from dependency_graph_construction_without_tokenize import DependencyBasedGraphConstruction_without_tokenizer
  from line_graph_construction import LineBasedGraphConstruction
label_desc: Use image node_id 1 for calling the ConllDataset obj's underlying member method code with example usage: obj.raw_file_names() and returns: dict