現有一個內容不規范的json文件（books.json），需要用Python的json_normalize()函數將其標準化file=open('books.json','r')text=file.read()text=json.loads（text）json_normalize(text,'book')運行出現錯誤“raise JSONDecodeError("Expecting value", s, err.value) from NoneJSONDecodeError: Expecting value”是怎么回事呢json文件的內容是：[{"writer":"Mark Ross","nationality":"USA","books":[? ? ? ? {"title":"XML Cookbook","price":23.56},? ? ? ? {"title":"Python Fundamentals","price":50.70},? ? ? ? {"title":"The NumPy library","price":12.30}]? ? },? ? {"writer":"Barbara Bracket","nationality":"UK","books":[? ? ? ? ? ?{ "title":"Java Enterprise","price":28.60},? ? ? ? ? ?{"title":"HTML5","price":31.35},? ? ? ? ? ?{"title":"Python for Dummies","price":28.00}? ? ? ? ? ?]? ? }]