Get configured tags.

def __get_tags(vm_):
    '''
    Get configured tags.
    '''
    t = config.get_cloud_config_value(
        'tags', vm_, __opts__,
        default='[]', search_global=False)
    # Consider warning the user that the tags in the cloud profile
    # could not be interpreted, bad formatting?
    try:
        tags = literal_eval(t)
    except Exception:  # pylint: disable=W0703
        tags = None
    if not tags or not isinstance(tags, list):
        tags = None
    return tags