Helper function to compare release codename versions to the minion's current
    Salt version.

    If release codename isn't found, the function returns None. Otherwise, it
    returns the results of the version comparison as documented by the
    ``versions_cmp`` function in ``salt.utils.versions.py``.

def _check_release_cmp(name):
    '''
    Helper function to compare release codename versions to the minion's current
    Salt version.

    If release codename isn't found, the function returns None. Otherwise, it
    returns the results of the version comparison as documented by the
    ``versions_cmp`` function in ``salt.utils.versions.py``.
    '''
    map_version = get_release_number(name)
    if map_version is None:
        log.info('Release codename %s was not found.', name)
        return None

    current_version = six.text_type(salt.version.SaltStackVersion(
        *salt.version.__version_info__))
    current_version = current_version.rsplit('.', 1)[0]
    version_cmp = salt.utils.versions.version_cmp(map_version, current_version)

    return version_cmp