求助：python爬取12306车票信息总是出现错误

最近初学python，进展到网络爬虫部分，尝试自己写一下查票，结果遇到了麻烦

import requests
url = 'https://kyfw.12306.cn/otn/leftTicket/queryZ?' \
      'leftTicketDTO.train_date=2020-02-01&' \
      'leftTicketDTO.from_station=SHH&' \
      'leftTicketDTO.to_station=BJP&purpose_codes=ADULT'
result=requests.get(url)
print(result.json())

出现的问题如下：

Traceback (most recent call last):
  File "D:/Files/check tickets/123.py", line 7, in <module>
    print(result.json())
  File "D:\Files\python3\lib\site-packages\requests\models.py", line 897, in json
    return complexjson.loads(self.text, **kwargs)
  File "D:\Files\python3\lib\json\__init__.py", line 357, in loads
    return _default_decoder.decode(s)
  File "D:\Files\python3\lib\json\decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "D:\Files\python3\lib\json\decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

不知如何解决，求解答，谢谢！