def METHOD_NAME(repo: PathLike, checksum: str) -> str:
    """Show the metada of an OSTree object pointed by `checksum` in the repository at `repo`"""
    repo = os.fspath(repo)
    if isinstance(repo, bytes):
        repo = repo.decode("utf8")
    r = subprocess.run(["ostree", "show", f"--repo={repo}", checksum],
                       encoding="utf8",
                       stdout=subprocess.PIPE,
                       stderr=subprocess.STDOUT,
                       check=False)
    msg = r.stdout.strip()
    if r.returncode != 0:
        raise RuntimeError(msg)
    return msg