Delete a group from the cache backend

def delete_group_cached(group_id, broker=None):
    """
    Delete a group from the cache backend
    """
    if not broker:
        broker = get_broker()
    group_key = '{}:{}:keys'.format(broker.list_key, group_id)
    group_list = broker.cache.get(group_key)
    broker.cache.delete_many(group_list)
    broker.cache.delete(group_key)