Python version 3.9 does not allow mixing byte text and non byte text

In the use of python When crawling through the question bank , Unable to crawl the text of the title in the diagram , The crawled content is empty , When I tried to assign this text to a variable, something came up "Python edition 3.9 It is not allowed to mix byte text and non byte text " The error of , How to solve it ？

import jsontitleText = 'st=("a","b")st[0]="c"print(st) The result of the program is ：('c','b')'json_path = "judgeAnswer.json"data = []with open(json_path, 'r') as loadFile: data = json.load(loadFile)print("load Json file :", data)print("\n")for item_dict in data: if item_dict["Title:"] == titleText: print(" subject ：", titleText) print(" Question bank search ：", item_dict)