class_docstr: Override TorchRankerAgent to include label in fixed cands set.
  
  Necessary for certain IR tasks where given candidate set does not contain example
  labels.
class_docstr_tok: ["Override","TorchRankerAgent","to","include","label","in","fixed","cands","set",".","Necessary","for","certain","IR","tasks","where","given","candidate","set","does","not","contain","example","labels","."]
docstr: Override to include new arg.
docstr_tok: ["Override","to","include","new","arg","."]
code: def add_cmdline_args(
      cls, parser: ParlaiParser, partial_opt: Optional[Opt] = None
  ) -> ParlaiParser:
      """
      Override to include new arg.
      """
      super().add_cmdline_args(parser, partial_opt=partial_opt)
      agent = parser.add_argument_group("AddLabelFixedCandsTRA")
      agent.add_argument(
          "--add-label-to-fixed-cands",
          type="bool",
          default=True,
          hidden=True,
          help="When true, adds an example label to the fixed candidate set "
          "if not already present",
      )
      return parser
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  import torch
  from .transformer import TransformerRankerAgent
  from parlai.core.torch_ranker_agent import TorchRankerAgent
label_desc: Use image node_id 2 for calling the AddLabelFixedCandsTRA obj's underlying member method code with example usage: obj.add_cmdline_args(cls, parser, partial_opt) and returns: parser