code: def setupViewletByName(self, name):
          
          context = aq_inner(self.context)
          request = self.request
  
          # Perform viewlet regisration look-up
          # from adapters registry
          reg = self.getViewletByName(name)
          if reg is None:
              return None
  
          # factory method is responsible for creating the viewlet instance
          factory = reg.factory
  
          # Create viewlet and put it to the acquisition chain
          # Viewlet need initialization parameters: context, request, view
          try:
              viewlet = factory(context, request, self, None).__of__(context)
          except TypeError:
              # Bad constructor call parameters
              raise RuntimeError(
                  "Unable to initialize viewlet {}. "
                  "Factory method {} call failed."
                  .format(name, str(factory)))
  
          return viewlet
docs: Constructs a viewlet instance by its name.
  
          Viewlet update() and render() method are not called.
  
          @return: Viewlet instance of None if viewlet with name does not exist