def add_args(parser):
        """Add task-specific arguments to the parser."""
        # fmt: off
        parser.add_argument('data', help='colon separated path to data directories list, \
                            will be iterated upon during epochs in round-robin manner; \
                            however, valid and test data are always in the first directory to \
                            avoid the need for repeating them in all directories')
        parser.add_argument('-s', '--source-lang', default=None, metavar='SRC',
                            help='source language')
        parser.add_argument('-t', '--target-lang', default=None, metavar='TARGET',
                            help='target language')
        parser.add_argument('--load-alignments', action='store_true',
                            help='load the binarized alignments')
        parser.add_argument('--left-pad-source', default='True', type=str, metavar='BOOL',
                            help='pad the source on the left')
        parser.add_argument('--left-pad-target', default='False', type=str, metavar='BOOL',
                            help='pad the target on the left')
        parser.add_argument('--max-source-positions', default=1024, type=int, metavar='N',
                            help='max number of tokens in the source sequence')
        parser.add_argument('--max-target-positions', default=1024, type=int, metavar='N',
                            help='max number of tokens in the target sequence')
        parser.add_argument('--upsample-primary', default=1, type=int,
                            help='amount to upsample primary dataset')
        parser.add_argument('--truncate-source', action='store_true', default=False,
                            help='truncate source to max-source-positions')
        parser.add_argument('--num-batch-buckets', default=0, type=int, metavar='N',
                            help='if >0, then bucket source and target lengths into N '
                                 'buckets and pad accordingly; this is useful on TPUs '
                                 'to minimize the number of compilations')

        # options for reporting BLEU during validation
        parser.add_argument('--eval-bleu', action='store_true',
                            help='evaluation with BLEU scores')
        parser.add_argument('--eval-bleu-detok', type=str, default="space",
                            help='detokenize before computing BLEU (e.g., "moses"); '
                                 'required if using --eval-bleu; use "space" to '
                                 'disable detokenization; see fairseq.data.encoders '
                                 'for other options')
        parser.add_argument('--eval-bleu-detok-args', type=str, metavar='JSON',
                            help='args for building the tokenizer, if needed')
        parser.add_argument('--eval-tokenized-bleu', action='store_true', default=False,
                            help='compute tokenized BLEU instead of sacrebleu')
        parser.add_argument('--eval-bleu-remove-bpe', nargs='?', const='@@ ', default=None,
                            help='remove BPE before computing BLEU')
        parser.add_argument('--eval-bleu-args', type=str, metavar='JSON',
                            help='generation args for BLUE scoring, '
                                 'e.g., \'{"beam": 4, "lenpen": 0.6}\'')
        parser.add_argument('--eval-bleu-print-samples', action='store_true',
                            help='print sample generations during validation')
        # fmt: on
Add task-specific arguments to the parser.
decoding/IAD/fairseq/fairseq/tasks/translation.py