static Object first(Object list) {
  return empty((List) list) ? null : ((List) list).get(0);
}

static <A> A first(L<A> list) {
  return empty(list) ? null : list.get(0);
}

static <A> A first(A[] bla) {
  ret bla == null || bla.length == 0 ? null : bla[0];
}

static <A> A first(Iterable<A> i) {
  if (i == null) ret null;
  Iterator<A> it = i.iterator();
  ret it.hasNext() ? it.next() : null;
}