Getting Historical Bars from ByBit API with Python

import requests 
import json 
import pandas as pd
import datetime as dt
import matplotlib.pyplot as plt
import qgrid
import time

def get_bybit_bars(symbol, interval, startTime, endTime):

    url = "https://api.bybit.com/v2/public/kline/list"

    startTime = str(int(startTime.timestamp()))
    endTime   = str(int(endTime.timestamp()))

    req_params = {"symbol" : symbol, 'interval' : interval, 'from' : startTime, 'to' : endTime}

    df = pd.DataFrame(json.loads(requests.get(url, params = req_params).text)['result'])

    if (len(df.index) == 0):
        return None
    
    df.index = [dt.datetime.fromtimestamp(x) for x in df.open_time]

    return df

get_bybit_bars('ETHUSD', 1, dt.datetime(2020, 1, 1), dt.datetime(2020, 2, 1))

df_list = []
last_datetime = dt.datetime(2018, 1, 1)
while True:
    print(last_datetime)
    new_df = get_bybit_bars("BTCUSD", 1, last_datetime, dt.datetime.now())
    if new_df is None:
        break
    df_list.append(new_df)
    last_datetime = max(new_df.index) + dt.timedelta(0, 1)

df = pd.concat(df_list)