    def add_args(parser):
        """Add model-specific arguments to the parser."""
        parser.add_argument(
            "--input-feat-per-channel",
            type=int,
            metavar="N",
            help="encoder input dimension per input channel",
        )
        parser.add_argument(
            "--vggblock-enc-config",
            type=str,
            metavar="EXPR",
            help="""
    an array of tuples each containing the configuration of one vggblock:
    [(out_channels,
      conv_kernel_size,
      pooling_kernel_size,
      num_conv_layers,
      use_layer_norm), ...])
            """,
        )
        parser.add_argument(
            "--transformer-enc-config",
            type=str,
            metavar="EXPR",
            help=""""
    a tuple containing the configuration of the encoder transformer layers
    configurations:
    [(input_dim,
      num_heads,
      ffn_dim,
      normalize_before,
      dropout,
      attention_dropout,
      relu_dropout), ...]')
            """,
        )
        parser.add_argument(
            "--enc-output-dim",
            type=int,
            metavar="N",
            help="""
    encoder output dimension, can be None. If specified, projecting the
    transformer output to the specified dimension""",
        )
        parser.add_argument(
            "--in-channels",
            type=int,
            metavar="N",
            help="number of encoder input channels",
        )
        parser.add_argument(
            "--tgt-embed-dim",
            type=int,
            metavar="N",
            help="embedding dimension of the decoder target tokens",
        )
        parser.add_argument(
            "--transformer-dec-config",
            type=str,
            metavar="EXPR",
            help="""
    a tuple containing the configuration of the decoder transformer layers
    configurations:
    [(input_dim,
      num_heads,
      ffn_dim,
      normalize_before,
      dropout,
      attention_dropout,
      relu_dropout), ...]
            """,
        )
        parser.add_argument(
            "--conv-dec-config",
            type=str,
            metavar="EXPR",
            help="""
    an array of tuples for the decoder 1-D convolution config
        [(out_channels, conv_kernel_size, use_layer_norm), ...]""",
        )
Add model-specific arguments to the parser.
examples/speech_recognition/models/vggtransformer.py