def METHOD_NAME(artifact_repository_url: str) -> Optional[List[Dict[str, Any]]]:
    """
    Returns a list of JSON objects representing docker images found under
    |artifact_repository_url|, or None on error.
    Sample JSON object:
    {
      "createTime": "2022-07-11T20:20:23.577823Z",
      "package": "us-docker.pkg.dev/stadia-open-source/amdvlk-public-ci/amdvlk_release_gcc_assertions",
      "tags": "",
      "updateTime": "2022-07-11T20:20:23.577823Z",
      "version": "sha256:e101b6336fa78014e4008df59667dd84616dc8d1b60c2240f3246ab9a1ed6b20"
    }
    """
    ok, text = _run_cmd(['gcloud', 'artifacts', 'docker', 'images', 'list',
                         artifact_repository_url, '--format=json', '--quiet'])
    if not ok:
        return None
    return list(json.loads(text))