I closed the last pr I submitted and downloaded the latest version to manually sync my code. But this automatic test tool still reports an error, I am not very clear about the meaning of this error.

This is my first time to submit pr on github, not very clear about the operation process, and my english is not very good, I am sorry！

Please, rebase
Otherwise looks OK

see https://help.github.com/en/articles/about-git-rebase#rebasing-commits-against-a-branch

请参阅https://help.github.com/en/articles/about-git-rebase#rebasing-commits-against-a-branch

you want i combine multiple commits into one？is it okay now？
Sorry, the first time I use this command

Ok, I'll try to provide instructions

you want i combine multiple commits into one？i

no, you need to git checkout master and git pull origin master where origin is this repository, not you fork.
after that, go back to you branch git checkout your_branch and run interactive rebase: git rebase -i master
You'll face conflicts (in smpplib/client.py) and you need to fix them using meld or similar tool.
Once conflicts fixed and rebase is finished, please do git push -f your_fork your_branch.

I needed that feature and even though the PR hasn't been merged, I was able to use your code @ywshzh and I wanted to thank you very much. It works like a charm. I skipped a migraine here.