def _version_list(app_id, max_count):

    if max_count is not None:
        max_count = util.parse_int(max_count)

    client = marathon.create_client()

    versions = client.get_app_versions(app_id, max_count)

    emitter.publish(versions)
    return 0
:param app_id: the id of the application
dataset/ETHPy150Open dcos/dcos-cli/cli/dcoscli/marathon/main.py/_version_list