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": "train.txt", "test": "test.txt"}
  
imports: import nltk
  from ..data.dataset import Text2LabelDataset
label_desc: Use image node_id 1 for calling the TrecDataset obj's underlying member method code with example usage: obj.raw_file_names() and returns: dict