Python interpolation not work about ultisnips HOT 2 CLOSED

I cannot reproduce this with the information alone, please provide a fully reproducible example, ideally using the approach explained in https://github.com/SirVer/ultisnips/blob/master/CONTRIBUTING.md#reproducing-bugs or if not possible with a minimal vimrc and snippets files and an exact sequence of key strokes that trigger the bug.

Also disclaimer re Neovim and not core Vim.

Why is Neovim only best-effort?

UltiSnips maintenance is a lot of work. Reproducing bug reports is tedious, slow and error prone. The current maintainers have to limit their scope to provide a reasonable level of service to the community.

Neovim should work with any plugin that core vim works with. But in the past, Neovim support has been difficult for UltiSnips: It regularly had bugs that did not affect the core Vim distributions, i.e. Vim, gVim, MacVim, and Vim for Windows and its testing approach required a completely separate code path from core as well. Therefore, currently Neovim bugs are considered on a best effort basis.

UltiSnips is looking for an additional maintainer that is interested in bringing the Neovim level of service on par with core Vim. If you are interested in helping out, please reach out to SirVer.

from ultisnips.

I tried to delete all related settings in vimrc and reinstall Ultisnips but it still not work. Sometimes the snippets work though I did nothing, which confuse me a lot, and I don't know which part I do wrong.

from ultisnips.