def get_genome_dir(infra_id, genver=None, annver=None, key=None):
    """Return the genome directory name from infra_id and optional arguments."""
    dirname = f"{infra_id}"
    if genver is not None:
        dirname += f".gnm{genver}"
    if annver is not None:
        dirname += f".ann{annver}"
    if key is not None:
        dirname += f".{key}"
    return dirname