The system you work with on a daily basis runs multiple microservices. You have been asked to prepare an aggregation that represents the number o user visits to all microservices, for use by data analysts. The architect you're working with has already designed the API, which consists of a single class: VisitCounter. VisitCounter has a single method, count. It returns Map<Long, Long> - this map should contain the number of visits by the user with a given ID. This method accepts an array of Map<String, UserStats>. Every map represents the total number of visits per user to a given microservice. There are some problems, however: The map key, which is a String should be parseable to Long - but it may not be. You must skip any such faulty entries. For some keys, UserStats may be null. You must skip any such faulty entries. UserStats has a single field, visitCount, of type Optional<Long>. A getter for this field is also implemented. This field will never be null; however it might be empty. You must skip any sch faulty entries. Remember that you may receive some invalid input: null, empty maps, and so on. Handle it all appropriately and return an empty map. Assumptions: The UserStats class is already implemented. You do not have to write the implementation of this class as part of your solution.