cython linter is here

[00sapo]

require("lint").linters.cython = {
  name = "cython",
  cmd = "cython",
  stdin = false, -- or false if it doesn't support content input via stdin. In that case the filename is automatically added to the arguments.
  append_fname = true, -- Automatically append the file name to `args` if `stdin = false` (default: true)
  -- add time to the output file
  args = { "-Wextra", "-o", ".cython_linter_output" }, -- list of arguments. Can contain functions with zero arguments that will be evaluated once the linter is used.
  stream = "both", -- ('stdout' | 'stderr' | 'both') configure the stream to which the linter outputs the linting result.
  ignore_exitcode = true, -- set this to true if the linter exits with a code != 0 and that's considered normal.
  env = nil, -- custom environment table to use with the external process. Note that this replaces the *entire* environment, it is not additive.
  parser = function(output, bufnr, cwd)
    local result = {}
    local pattern1 = "([%w ]*):? ?([^:]+):(%d+):(%d+): (.+)"
    local pattern2 = "([^:]+):(%d+):(%d+): (.+)"
    for line in output:gmatch("[^\n]+") do
      local severities = {
        ["error"] = vim.diagnostic.severity.ERROR,
        ["warning"] = vim.diagnostic.severity.WARN,
        ["information"] = vim.diagnostic.severity.INFO,
        ["performance hint"] = vim.diagnostic.severity.HINT,
      }
      local file, lnum, col, message
      local severity = line:match("^[^:]+")
      if severity == "warning" or severity == "information" or severity == "performance hint" then
        severity, file, lnum, col, message = line:match(pattern1)
      else
        severity = "error"
        file, lnum, col, message = line:match(pattern2)
      end
      if file then
        local diagnostic = {
          bufnr = bufnr,
          file = file,
          lnum = tonumber(lnum) - 1,
          col = tonumber(col),
          message = message,
          severity = severities[severity],
          source = "cython",
        }
        table.insert(result, diagnostic)
      end
    end
    return result
  end,
}

[mfussenegger]

Okay? If you want this included, please create a PR