code: def enter(clsQname):
      
      def wrapper(routeHandler):
          @functools.wraps(routeHandler)
          def inner(self, request, *a, **kw):
              if getattr(inner, '_subKlein', None) is None:
                  cls = namedAny(clsQname)
                  inner._subKlein = cls().app.resource()
              return routeHandler(self, request, inner._subKlein, *a, **kw)
          inner._subKleinQname = clsQname
          return inner
      return wrapper
docs: Delegate a rule to another class which instantiates a Klein app
  
      This also memoizes the resource instance on the handler function itself