UltiSnips | The ultimate snippet solution for python enabled Vim | Text Editor library

I believe the syntax is incorrect, in the docs you can see that there's a section to customize a source.

Using this, I've customized the buffer source like so:

The error is came from coc-python, but coc-python is deprecated, https://github.com/neoclide/coc-python#coc-python, try coc-pyright or coc-jedi.

Vim colorschemes typically define styling attributes for basic terminals (term), color terminals (cterm*), and GUI (gui*). Here is an example:

Welcome to Vim!

I think most new vim users have been there. I certainly have! I wanted a 'vim as python IDE' and copied a whole bunch of stuff from every blog under the sun into my vimrc almost immediately after installing vim.

After some time spent fighting with all the settings, plugins and remaps I didn't understand, I decided to go through my vimrc, line by line and comment out anything I didn't understand (nearly all of it).

Then I used this more minimal vim for a while and whenever I decided I had a need for a certain feature, I checked the largely commented vimrc for anything that looked related, and/or googled for that particular feature only. Often you find that there is a built in method to do it with the core vim commands, and if not, then there are a lot of solutions for the problem (and often, you find that there is an even more powerful way that didn't occur to you - these are good days).

But the key is to not try and coerce vim into a huge IDE overnight! Let it happen gradually and things will make more sense, and you'll end up with a vimrc that you understand and therefore be in a position to add to it and tweak it.

The last thing I'll say is to recommend the following books:
'Learn VimScript the Hard Way' by Steve Losh
'Practical Vim' by Drew Neil, and his accompanying screencast series.
(Also there is The Primagean who does high quality youtube tutorials)

Having said all that, and acknowledging that an objective answer can't be given for your question, here is a minimal vimrc which has a few plugins and settings that do simple but very useful things (but do read up on them to understand how they work!):

In this case the snippet is not expanded because it is preceded by $ without any whitespace in between. Try adding i to the first line of the snippet:

Set diagnostic.refreshOnInsertMode to true in your coc-settings.json.

You may need run git reset head --hard in folder of coc.nvim and update it by :PlugUpdate in your vim.

The foo in foo.snippets doesn't refer to the .foo extension, but to the foo filetype, that Vim may or may not derive from the .foo extension.

In this case, Vim assigns the text filetype to files with the .txt extension so your snippets, which depend on the txt filetype, are not active.

Renaming your snippet file to text.snippets should solve your problem.

Your error is mostly because you don't have the pynvim Python package installed. Do a pip install pynvim and it should work.

Be careful because I couldn't make it work with latest version of python (3.9), as it says it needs Build Tools for C++.