TypeError: can't set attributes of built-in/extension type 'set'，这个是什么情况？
Traceback (most recent call last):
File "D:/Python/Python工程文件/Pythonreptile/Spider_main.py", line 36, in <module>
obj_spider = SpiderMain()
File "D:/Python/Python工程文件/Pythonreptile/Spider_main.py", line 8, in __init__
self.urls = url_manager.UrlManager() # ，模块：管理器
File "D:\Python\Python工程文件\Pythonreptile\url_manager.py", line 5, in __init__
set.new_urls = set()
TypeError: can't set attributes of built-in/extension type 'set'
