docs: def rootURL(self, request):
          """
          Simple utility function to provide a root URL for this website which is
          appropriate to use in links generated in response to the given request.
  
          @type request: L{twisted.web.http.Request}
          @param request: The request which is being responded to.
  
          @rtype: L{URL}
          @return: The location at which the root of the resource hierarchy for
              this website is available.
          """
          warnings.warn(
              "Use ISiteURLGenerator.rootURL instead of WebSite.rootURL.",
              category=DeprecationWarning,
              stacklevel=2)
          if self.store.parent is not None:
              generator = ISiteURLGenerator(self.store.parent)
          else:
              generator = ISiteURLGenerator(self.store)
          return generator.rootURL(request)