Why it is dict, STR is error say?-CodePudding

 
The import json 

If __name__=="__main__" : 
A=6 
For num range in (a) : 
B=0 
With the open (' collect - test/default bookmarks' + STR (num + 1) + 'json', 'r', encoding="utf-8") as f: 
Whole=json. The load (f) 
Data=https://bbs.csdn.net/topics/whole (' data ') 
Medias=data [' medias'] 
With the open (' collect - test/default bookmarks. Json ', 'ab +) as fp: 
For I in medias: 
Json. Dump (I, fp)

Line 13 error: TypeError: a bytes - like the object is required, not 'STR'
I put into a dict I (I) to the wrong, why?