小编use*_*121的帖子

我是 Flask 的新手，开始遵循这个视频教程...我昨天完成了它，今天又回到了它，其中完全相同的代码在那之前运行良好，开始显示以下错误：

    Traceback (most recent call last):
  File "app.py", line 5, in <module>
    app = Flask(__name__)
  File "C:\Users\VS\AppData\Local\Programs\Python\Python38-32\lib\site-packages\flask\app.py", line 558, in __init__
    self.add_url_rule(
  File "C:\Users\VS\AppData\Local\Programs\Python\Python38-32\lib\site-packages\flask\app.py", line 66, in wrapper_func
    return f(self, *args, **kwargs)
  File "C:\Users\VS\AppData\Local\Programs\Python\Python38-32\lib\site-packages\flask\app.py", line 1216, in add_url_rule
    self.url_map.add(rule)
  File "C:\Users\VS\AppData\Local\Programs\Python\Python38-32\lib\site-packages\werkzeug\routing.py", line 1562, in add
    rule.bind(self)
  File "C:\Users\VS\AppData\Local\Programs\Python\Python38-32\lib\site-packages\werkzeug\routing.py", line 711, in bind
    self.compile()
  File "C:\Users\VS\AppData\Local\Programs\Python\Python38-32\lib\site-packages\werkzeug\routing.py", line 767, in compile
    self._build = self._compile_builder(False)
  File "C:\Users\VS\AppData\Local\Programs\Python\Python38-32\lib\site-packages\werkzeug\routing.py", line 1128, in _compile_builder       
    return self.BuilderCompiler(self).compile(append_unknown)
  File "C:\Users\VS\AppData\Local\Programs\Python\Python38-32\lib\site-packages\werkzeug\routing.py", line 1119, in compile …