docstr: At least 2 reserved keys should be fiiled: 'vocab' and 'data'.
docstr_tok: ["At","least","2","reserved","keys","should","be","fiiled",":","'vocab","'","and","'data","'","."]
code: def processed_file_names(self):
      """At least 2 reserved keys should be fiiled: 'vocab' and 'data'."""
      return {"vocab": "vocab.pt", "data": "data.pt"}
  
imports: import nltk
  from ..data.dataset import DoubleText2TextDataset
label_desc: Use image node_id 2 for calling the SQuADDataset obj's underlying member method code with example usage: obj.processed_file_names() and returns: dict