download_bars

def main(start_datetime_str: str, end_datetime_str: Optional[str],
         base_currency: str, quote_currency: str):
    url = f"https://api-pub.bitfinex.com/v2/candles/trade:1h:t{base_currency}{quote_currency}/hist"

    params = {
        "limit": 5000,
        "sort": 1,
        "start": datetime.datetime.strptime(start_datetime_str, strftime_days).timestamp() * 1000,
        "end": datetime.datetime.strptime(end_datetime_str, strftime_days).timestamp() * 1000
    }

    bars = requests.get(url, params=params).json()

    with open(f'bitfinex_bars_{base_currency}{quote_currency}.csv', 'w+') as output:
        writer = csv.writer(output)
        writer.writerow(["timestamp", "open", "close", "high", "low", "volume_base"])
        while len(bars) > 0:
            writer.writerows(bars)
            params["start"] = bars[-1][0]
            print('first', microsecond_timestamp_to_utc_datetime(bars[0][0]), 'last', microsecond_timestamp_to_utc_datetime(bars[-1][0]))
            bars = requests.get(url, params=params).json()

            if bars[0] == 'error':
                print('done')
                return