    def add_args(cls, parser):
        """Add model-specific arguments to the parser."""
        XMTransformerModel.add_args(parser)
        parser.add_argument(
            "--translation-decoder-layers",
            type=int,
            default=4,
            metavar="N",
            help="num decoder layers in the first-pass translation module",
        )
        parser.add_argument(
            "--synthesizer-encoder-layers",
            type=int,
            default=0,
            metavar="N",
            help="num encoder layers in the second-pass synthesizer module",
        )
        parser.add_argument(
            "--synthesizer-augmented-cross-attention",
            action="store_true",
            default=False,
            help="augmented cross-attention over speech encoder output",
        )
        parser.add_argument(
            "--load-pretrained-aux-decoder-from",
            type=str,
            metavar="STR",
            help="model to take decoder weights from (for initialization)",
        )
Add model-specific arguments to the parser.
fairseq/models/speech_to_text/xm_transformer_unity.py