How to use the trustme._KEY_SIZE function in trustme

"-q",
        "--quiet",
        action="store_true",
        help="Doesn't print out helpful information for humans",
    )

    args = parser.parse_args(argv or sys.argv[1:])
    if len(args.identities) < 1:
        raise ValueError("Must include at least one identity")
    cert_dir = pathlib.Path(args.dir)
    if not cert_dir.is_dir():
        raise ValueError(f"--dir={cert_dir} is not a directory")
    common_name = args.common_name[0] if args.common_name else None

    # Generate the CA certificate
    trustme._KEY_SIZE = args.key_size
    ca = trustme.CA()
    cert = ca.issue_cert(*args.identities, common_name=common_name)

    # Write the certificate and private key the server should use
    server_key = cert_dir / "server.key"
    server_cert = cert_dir / "server.pem"
    cert.private_key_pem.write_to_path(path=str(server_key))
    with server_cert.open(mode="w") as f:
        f.truncate()
    for blob in cert.cert_chain_pems:
        blob.write_to_path(path=str(server_cert), append=True)

    # Write the certificate the client should trust
    client_cert = cert_dir / "client.pem"
    ca.cert_pem.write_to_path(path=str(client_cert))