它在今天之前一直在工作。我不知道为什么它今天不起作用。

import yfinance as yf
df = yf.Ticker('MMM').history(start='2021-01-01',end='2021-07-10')

File "D:\anaconda3\envs\tensorflow\lib\site-packages\yfinance\base.py", line 157, in history
data = data.json()
File "D:\anaconda3\envs\tensorflow\lib\site-packages\requests\models.py", line 900, in json
return complexjson.loads(self.text,**kwargs)
File "D:\anaconda3\envs\tensorflow\lib\json\__init__.py", line 357, in loads
return _default_decoder.decode(s)
File "D:\anaconda3\envs\tensorflow\lib\json\decoder.py", line 337, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "D:\anaconda3\envs\tensorflow\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)