public Call<Event> createEvent(Event e) {
   return service.createEvent(
       e.getUser_id(),
       e.getEvent_details(),
       e.getEvent_name(),
       e.getLocation(),
       e.getStart_time(),
       e.getEnd_time());
 }
 public Call<Event> getEventById(String id) {
   return service.getEventById(id);
 }
 public Call<List<Event>> getAttendingEvents(String userId) {
   return service.getAttendingEvents(userId);
 }