def add_args(parser):
        """Add optimizer-specific arguments to the parser."""
        # fmt: off
        parser.add_argument('--weight-decay', '--wd', default=0.0, type=float, metavar='WD',
                            help='weight decay')
        # fmt: on
Add optimizer-specific arguments to the parser.
understand_icl/fairseq/fairseq/optim/adagrad.py