def compose_redis_key(vim_name, identifier, identifier_type="vdu"):
    """Compose the key for redis given vim name and vdu uuid

    Args:
        vim_name (str): The VIM name
        identifier (str): The VDU or VNF uuid (NFVI based)
        identifier_type (str): the identifier type. Default type is vdu. Also vnf is supported.

    Returns:
        str: the key for redis
    """
    if identifier_type == "vnf":
        return "{}:vnf#{}".format(vim_name.lower(), identifier)
    else:
        return "{}:{}".format(vim_name.lower(), identifier)