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                        /后端开发
                        
                            /Python
                        
                        /Python开发简单爬虫

运行最后面出现这个，哪里错了？

Traceback (most recent call last):
File "D:\work\imooc\baike_spider\spider_main.py", line 58, in <module>
    obj_spider.craw(root_url)
File "D:\work\imooc\baike_spider\spider_main.py", line 48, in craw
    self.outputer.output_html()
File "D:\work\imooc\baike_spider\html_outputer.py", line 23, in output_html
    fout.write("<td>%s</td>" % data['url'])
TypeError: 'set' object has no attribute '__getitem__'