def METHOD_NAME(filename, default="Packages/Text/Plain text.tmLanguage"):
    # type: (str, str) -> str
    if not syntax_functions_readied():
        return default
    syntaxes = (
        syntax_file_map.get(filename, [])
        or syntax_file_map.get(get_file_extension(filename), [])
        or maybe(lambda: [sublime.find_syntax_for_file(filename).path])  # type: ignore[union-attr]
        or [default]
    )
    return syntaxes[-1]