Double exclamation mark "python" variable in YAML fails in NeoVim

Hello,

Using Mkdocs with Material, the YAML file should sometimes use this:

markdown_extensions:
  - pymdownx.highlight:
      anchor_linenums: true
  - pymdownx.superfences:
      custom_fences:
        - name: mermaid
          class: mermaid
          format: !!python/name:pymdownx.superfences.fence_code_format

But... NeoVim with nvim-lspconfig fails to accept the !!python tag:

I tried many configurations...

• Adding tag:yaml.org,2002:python
• Adding tag:yaml.org,2002:python/name
• Adding !python
• Adding !python/name
• Adding !python/name scalar

And a dozen of others. This fails. Yamls-language-server continuously says that there is an error in the YAML file.

This is the configuration I have now, still doesn't work:

return {
  {
    "neovim/nvim-lspconfig",
    opts = {
      servers = {
        yamlls = {
          settings = {
            yaml = {
              validate = true,
              customTags = { "!!python/name" },
            },
          },
        },
      },
    },
  },
}

Thanks if someone can help me.

Start with the yamlls customTags setting and the YAML snippet shown in the issue, then trace how the language server parses and validates the !!python/name tag. Reproduce the diagnostic in NeoVim with nvim-lspconfig. Done means the valid tag is accepted without a YAML error.