Write a method hasDuplicateValues that, given a non-null Map<String, String>, returns true if the map contains duplicate values—meaning that two different keys map to the same value—and false otherwise. Recall that a map can never contain duplicate keys, since the second mapping from the same key overwrites the first.

You should use a Set to solve this problem! You do not need to import Map, Set, or HashSet, since these are already provided for you.