    def add_args(parser):
        """Add model-specific arguments to the parser."""
        parser.add_argument(
            "--dropout", type=float, metavar="D", help="dropout probability"
        )
        parser.add_argument(
            "--decoder-embed-dim",
            type=int,
            metavar="N",
            help="decoder embedding dimension",
        )
        parser.add_argument(
            "--decoder-layers",
            type=str,
            metavar="EXPR",
            help="decoder layers [(dim, kernel_size), ...]",
        )
        parser.add_argument(
            "--decoder-out-embed-dim",
            type=int,
            metavar="N",
            help="decoder output embedding dimension",
        )
        parser.add_argument(
            "--adaptive-softmax-cutoff",
            metavar="EXPR",
            help="comma separated list of adaptive softmax cutoff points. "
            "Must be used with adaptive_loss criterion",
        )
        parser.add_argument(
            "--adaptive-softmax-dropout",
            type=float,
            metavar="D",
            help="sets adaptive softmax dropout for the tail projections",
        )
        parser.add_argument(
            "--decoder-attention",
            type=str,
            metavar="EXPR",
            help="decoder attention [True, ...]",
        )
Add model-specific arguments to the parser.
fairseq/models/fconv_lm.py