尝试把tornado更新到5.1.1后 出现了这个代码，然后现在的问题还没有解决
ERROR: After October 2020 you may experience errors when installing or updating packages. This is because pip will change the way that it resolves dependency conflicts.
We recommend you use --use-feature=2020-resolver to test your packages with the new resolver before it becomes the default.
distributed 2.30.1 requires tornado>=6.0.3; python_version >= "3.8", but you'll have tornado 5.1.1 which is incompatible.
当前环境中安装了不兼容的版本。在这种情况下，distributed软件包需要tornado的版本至少为6.0.3，并且仅支持Python版本3.8及以上，但你的环境中安装的tornado版本是5.1.1，不符合要求。
先看看你的python版本是否符合要求，然后再升级下你的tornado版本到6.0.3及以上。祝顺利！