运行时候JSON报错

[hadeschan1985]

错误提示如下，PY 2.7环境下运行，操作系统WINDOWS 10

+++++正在解析第1页+++++
Traceback (most recent call last):
File "zhihu_picture_downloader.py", line 149, in
pics=get_pic_from_topic(id,offset)
File "zhihu_picture_downloader.py", line 116, in get_pic_from_topic
dat=json.loads(js_data.content)['msg']
File "C:\Python27\lib\json_init_.py", line 339, in loads
return _default_decoder.decode(s)
File "C:\Python27\lib\json\decoder.py", line 364, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "C:\Python27\lib\json\decoder.py", line 382, in raw_decode
raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded