@@ -0,0 +1,670 @@
+package com.google.tripmeout.frontend.storage;%0A%0Apublic class PersistentPlaceVisitStorage implements PlaceVisitStorage %7B%0A    void addPlaceVisit(PlaceVisitModel placeVisit) throws PlaceVisitAlreadyExistsException%7B%7D%0A%0A %0A  void removePlaceVisit(String tripId, String placeVisitId) throws PlaceVisitNotFoundException%7B%7D%0A%0A  %0A  Optional%3CPlaceVisitModel%3E getPlaceVisit(String tripId, String placeVisitId)%7B%7D%0A%0A  %0A  PlaceVisitModel updateUserMarkOrAddPlaceVisit(%0A      PlaceVisitModel placeVisit, PlaceVisitModel.UserMark newStatus)%7B%7D%0A%0A  %0A  List%3CPlaceVisitModel%3E getTripPlaceVisits(String tripId)%7B%7D%0A%0A %0A  void removeTripPlaceVisits(String tripId) throws TripNotFoundException%7B%7D%0A    %0A%7D

create Persistent storage class for Place Visit