def add_protein_sequence_args(parser):
    """
    Extends an ArgumentParser instance with the following args:
        --max-protein-sequences-per-variant
    Also adds all translation arguments such as:
        --protein-sequence-length
    """
    protein_sequence_group = parser.add_argument_group(
        "Protein sequences (grouping equivalent translations)")
    protein_sequence_group.add_argument(
        "--max-protein-sequences-per-variant",
        type=int,
        default=MAX_PROTEIN_SEQUENCES_PER_VARIANT)
    return protein_sequence_group