Traceback (most recent call last): File "/usr/share/nginx/MahjongSite/venv/lib/python3.9/site-packages/tornado/web.py", line 1784, in _execute result = method(*self.path_args, **self.path_kwargs) File "/usr/share/nginx/MahjongSite/main.py", line 122, in get if len(player) == 0: TypeError: object of type 'NoneType' has no len()