code: def _resolve_by_settings_urls(request, url, urlconf=None):
      
      mapping = getattr(settings, 'NAVIGATION_URL_MAP', {})
      title = mapping.get(url, None)
      if title is not None:
          if hasattr(title, '__call__'):
              title = title(request)
  #            try:
  #                endpoint, args, kwargs = _resolve_url(url, request,
  #                                                      urlconf=urlconf)
  #            except urlresolvers.Resolver404:
  #                # call at least somehow
  #                title = title(request)#, *args, **kwargs)
  #            else:
  #                # call with full params
  #                title = title(request, *args, **kwargs)
          return Crumb(url, title)
docs: Finds appropriate URL in settings dictionary ``NAVIGATION_URL_MAP`` and
      returns the Crumb object based on the value. The values can be strings or
      functions (or any callables). The functions are called as views. The
      callable values do not require that an existing endpoint and always get
      only one argument: the ``request`` object.