//	@SuppressWarnings("unchecked")
	public static <A, T> Map<A, Collection<T>> group(Collection<T> col, String groupBy) {
		F1<T,A> groupF = new F1<T,A>() {public A e(T obj) {
			return (A) BeanUtil4.getAttribute(groupBy, obj);
		}};
		
		return group(col, groupF);
	}