How to use the technical.exchange.historical_data function in technical

def test_historical_data():
    days = datetime.datetime.today() - datetime.timedelta(days=7)
    print(days)
    data = historical_data(
        "USDT", "BNB", "1d", days.timestamp())

    assert len(data) == 7

def test_historical_data_ploniex_long():
    """ this one is awesome since you can download years worth of data"""
    days = datetime.datetime.today() - datetime.timedelta(days=365)

    data = historical_data(
        "BTC", "ETC", "1d", days.timestamp(), "poloniex")

    assert len(data) == 365

def test_historical_data_ploniex():
    """ this one is awesome since you can download years worth of data"""
    days = datetime.datetime.today() - datetime.timedelta(days=90)

    data = historical_data(
        "BTC", "ETH", "1d", days.timestamp(), "poloniex")

    assert len(data) == 90

latest_time = OHLCV.session.query(func.max(OHLCV.timestamp)).filter(
        OHLCV.exchange == ccxt_api.name,
        OHLCV.pair == "{}/{}".format(asset.upper(), stake.upper()),
        OHLCV.interval == interval
    ).one()[0]

    if force:
        print("forcing database refresh and downloading all data!")
        latest_time = None

    # add additional data on top
    if latest_time is None:

        # store data for all
        for row in historical_data(stake, asset, interval, from_date, ccxt_api):
            o = OHLCV(
                id="{}-{}-{}/{}:{}".format(ccxt_api.name, interval, asset.upper(), stake.upper(), row[0]),
                exchange=ccxt_api.name,
                pair="{}/{}".format(asset.upper(), stake.upper()),
                interval=interval,
                open=row[1],
                close=row[4],
                high=row[2],
                low=row[3],
                volume=row[5],
                timestamp=row[0]
            )
            OHLCV.session.merge(o)

    else:
        # calculate the difference in days and download and merge the data files

exchange=ccxt_api.name,
                pair="{}/{}".format(asset.upper(), stake.upper()),
                interval=interval,
                open=row[1],
                close=row[4],
                high=row[2],
                low=row[3],
                volume=row[5],
                timestamp=row[0]
            )
            OHLCV.session.merge(o)

    else:
        # calculate the difference in days and download and merge the data files

        for row in historical_data(stake, asset, interval, latest_time, ccxt_api):
            o = OHLCV(
                id="{}-{}-{}/{}:{}".format(ccxt_api.name, interval, asset.upper(), stake.upper(), row[0]),
                exchange=ccxt_api.name,
                pair="{}/{}".format(asset.upper(), stake.upper()),
                interval=interval,
                open=row[1],
                close=row[4],
                high=row[2],
                low=row[3],
                volume=row[5],
                timestamp=row[0]
            )
            OHLCV.session.merge(o)

    # return all data to user
    result = []