class_docstr: This is a composite loss that, given a list of model outputs and a list of targets,
  computes an average of losses for each output-target pair
docstr: Add criterion-specific arguments to the parser.
file_path: fairseq/fairseq/criterions/composite_loss.py
imports: from fairseq import utils
  from fairseq.criterions import LegacyFairseqCriterion, register_criterion
  from torch import nn
label_desc: Use image node_id 2 for calling the CompositeLoss obj's underlying member method code with example usage: obj.add_args(parser) without return types