docstr: At least 3 reserved keys should be fiiled: 'vocab', 'data' and 'label'.
docstr_tok: ["At","least","3","reserved","keys","should","be","fiiled",":","'vocab","'",",","'data","'","and","'label","'","."]
code: def processed_file_names(self):
      """At least 3 reserved keys should be fiiled: 'vocab', 'data' and 'label'."""
      return {
          "vocab": "vocab.pt",
          "data": "data.pt",
          "label": "label.pt",
      }
  
imports: import nltk
  from ..data.dataset import Text2LabelDataset
label_desc: Use image node_id 2 for calling the TrecDataset obj's underlying member method code with example usage: obj.processed_file_names() and returns: dict