docs: def produceResource(self, request, segments, webViewer):
          """
          Return a C{(resource, subsegments)} tuple or None, depending on whether
          I wish to return an L{IResource} provider for the given set of segments
          or not.
          """
          def thunk():
              cr = getattr(self, 'createResource', None)
              if cr is not None:
                  return cr()
              else:
                  return self.createResourceWith(webViewer)
          return self._produceIt(segments, thunk)