code: func (s *legacyRootAPIHandler) WebService() *restful.WebService {
  	mediaTypes, _ := negotiation.MediaTypesForSerializer(s.serializer)
  	ws := new(restful.WebService)
  	ws.Path(s.apiPrefix)
  	ws.Doc("get available API versions")
  	ws.Route(ws.GET("/").To(s.handle).
  		Doc("get available API versions").
  		Operation("getAPIVersions").
  		Produces(mediaTypes...).
  		Consumes(mediaTypes...).
  		Writes(metav1.APIVersions{}))
  	return ws
  }
docs: // AddApiWebService adds a service to return the supported api versions at the legacy /api.