報JSONDecondeError這種類型的錯誤的時候就要檢查下json格式是否是正確的了，這里提供一個http://www.bejson.com/
Traceback (most recent call last):
File "D:/python開發代碼/Python之路/作業/New_Credit_Shopping/core/login.py", line 27, in <module>
menu.menushow(current_user) #調用顯示菜單
File "D:\python開發代碼\Python之路\作業\New_Credit_Shopping\modules\menu.py", line 34, in menushow
shopping.PayShopping(current_user)
File "D:\python開發代碼\Python之路\作業\New_Credit_Shopping\modules\shopping.py", line 78, in PayShopping
Credit_info = json.loads(credit_file.read())
File "C:\python3.5\lib\json\__init__.py", line 319, in loads
return _default_decoder.decode(s)
File "C:\python3.5\lib\json\decoder.py", line 339, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "C:\python3.5\lib\json\decoder.py", line 357, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)