docstr: Add criterion-specific arguments to the parser.
docstr_tok: ["Add","criterion-specific","arguments","to","the","parser","."]
code: def add_args(parser):
      """Add criterion-specific arguments to the parser."""
      parser.add_argument(
          "--kd-weight",
          type=float,
          default=0.0,
          help=(
              "mixture weight between the knowledge distillation and",
              "negative log likelihood losses. Must be in [0.0, 1.0]",
          ),
      )
  
file_path: translate/pytorch_translate/research/knowledge_distillation/knowledge_distillation_loss.py
imports: import math
  import torch
  import torch.nn.functional
  from fairseq import utils
  from fairseq.criterions import LegacyFairseqCriterion, register_criterion
  from pytorch_translate import utils
label_desc: Use image node_id 2 for calling the KnowledgeDistillationCriterion obj's underlying member method code with example usage: obj.add_args(parser) without return types