code: public static <T> Set<T> minus(Set<T> self, Iterable<?> removeMe) {
          return minus(self, asCollection(removeMe));
      }
docs: Create a Set composed of the elements of the first Set minus the
  elements from the given Iterable.
  
  @param self     a Set object
  @param removeMe the items to remove from the Set
  @return the resulting Set
  @since 1.8.7