code: public static <K, V, A> int occurrencesOfAttribute(
              Map<K, V> map,
              Function<? super V, ? extends A> function,
              A object)
      {
          return Iterate.count(map.values(), Predicates.attributeEqual(function, object));
      }
docs: Return the number of occurrences where object is equal to the specified attribute in the specified map.