How to use the kraken.constants.EMPTY_LIST function in kraken

def get_ohlc_kraken(currency, date_start, date_end, period):

    final_url = get_ohlc_kraken_url(currency, date_start, date_end, period)

    err_msg = "get_ohlc_kraken called for {pair} at {timest}".format(pair=currency, timest=date_start)
    error_code, json_response = send_request(final_url, err_msg)

    if error_code == STATUS.SUCCESS:
        return get_ohlc_kraken_result_processor(json_response, currency, date_start, date_end)

    return EMPTY_LIST

def get_order_history_kraken_result_processor(json_document, pair_name):
    """
    json_document - response from exchange api as json string
    pair_name - for backwords compabilities
    """

    orders = EMPTY_LIST

    if is_error(json_document) or "closed" not in json_document["result"]:

        msg = "get_order_history_kraken_result_processor - error response - {er}".format(er=json_document)
        log_to_file(msg, ERROR_LOG_FILE_NAME)

        return orders

    for order_id in json_document["result"]["closed"]:
        new_order = Trade.from_kraken(order_id, json_document["result"]["closed"][order_id])
        if new_order is not None:
            orders.append(new_order)

    return orders

def get_history_kraken_result_processor(json_document, pair_name, timest):
    all_history_records = EMPTY_LIST

    if is_error(json_document):

        msg = "get_history_kraken_result_processor - error response - {er}".format(er=json_document)
        log_to_file(msg, ERROR_LOG_FILE_NAME)

        return all_history_records

    if pair_name in json_document["result"]:
        for rr in json_document["result"][pair_name]:
            all_history_records.append(TradeHistory.from_kraken(rr, pair_name, timest))

    return all_history_records

"oflags": "fciq",
 				"refid": null,
 				"opentm": 1509592448.2296
 			},
 		}
 	}
 }
    """

    post_details = get_open_orders_kraken_post_details(key, pair_name=None)

    err_msg = "check kraken open orders called"

    status_code, res = send_post_request_with_header(post_details, err_msg, max_tries=5)

    open_orders = EMPTY_LIST
    if status_code == STATUS.SUCCESS:
        open_orders = get_open_orders_kraken_result_processor(res, pair_name)

    return status_code, open_orders

def get_ohlc_kraken_result_processor(json_responce, currency, date_start, date_end):
    result_set = EMPTY_LIST

    if is_error(json_responce):

        msg = "get_ohlc_kraken_result_processor - error response - {er}".format(er=json_responce)
        log_to_file(msg, ERROR_LOG_FILE_NAME)

        return result_set

    if currency in json_responce["result"]:
        # "result":{"XXRPXXBT":[[1500873300,"0.00007037","0.00007055","0.00007012","0.00007053","0.00007035","104062.41283454",17],
        # [1500874200,"0.00007056","0.00007071","0.00007006","0.00007007","0.00007041","90031.72579746",33],
        for record in json_responce["result"][currency]:
            result_set.append(Candle.from_kraken(record, currency))

    return result_set

def get_history_kraken(pair_name, prev_time, now_time):

    final_url = get_history_kraken_url(pair_name, prev_time, now_time)

    err_msg = "get_history_kraken called for {pair} at {timest}".format(pair=pair_name, timest=now_time)
    status_code, json_document = send_request(final_url, err_msg)

    if status_code == STATUS.SUCCESS:
        return get_history_kraken_result_processor(json_document, pair_name, now_time)

    return EMPTY_LIST

def get_open_orders_kraken_result_processor(json_document, pair_name):
    open_orders = EMPTY_LIST

    if is_error(open_orders) or "open" not in json_document["result"]:

        msg = "get_open_orders_kraken_result_processor - error response - {er}".format(er=json_document)
        log_to_file(msg, ERROR_LOG_FILE_NAME)

        return open_orders

    for order_id in json_document["result"]["open"]:
        new_order = Trade.from_kraken(order_id, json_document["result"]["open"][order_id])
        if new_order is not None:
            open_orders.append(new_order)

    return open_orders