code: def resolution_order(lang, override=None):
      
      if not settings.ENABLE_FALLBACKS:
          return (lang,)
      if override is None:
          override = {}
      fallback_for_lang = override.get(lang, settings.FALLBACK_LANGUAGES.get(lang, ()))
      fallback_def = override.get('default', settings.FALLBACK_LANGUAGES['default'])
      order = (lang,) + fallback_for_lang + fallback_def
      return tuple(unique(order))
docs: Return order of languages which should be checked for parameter language.
      First is always the parameter language, later are fallback languages.
      Override parameter has priority over FALLBACK_LANGUAGES.