docstr: At least 3 reserved keys should be fiiled: 'vocab', 'data' and 'split_ids'.
docstr_tok: ["At","least","3","reserved","keys","should","be","fiiled",":","'vocab","'",",","'data","'","and","'split_ids","'","."]
code: def processed_file_names(self):
      """At least 3 reserved keys should be fiiled: 'vocab', 'data' and 'split_ids'."""
      return {"vocab": "vocab.pt", "data": "data.pt"}
  
imports: from graph4nlp.pytorch.data.dataset import Text2TreeDataset
label_desc: Use image node_id 2 for calling the MathQADatasetForTree obj's underlying member method code with example usage: obj.processed_file_names() and returns: dict