static AutoCloseable combineAutoCloseables(final AutoCloseable a, final AutoCloseable b) {
  ret a == null ? b : b == null ? a : autocloseable { pClose(a); pClose(b); };
}

static AutoCloseable combineAutoCloseables(AutoCloseable a, AutoCloseable b, AutoCloseable c, AutoCloseable... more) {
  ret combineAutoCloseables(concatLists(ll(a, b, c), asList(more)));
}

static AutoCloseable combineAutoCloseables(Iterable<AutoCloseable> l) {
  ret foldl(func(AutoCloseable a, AutoCloseable b) -> AutoCloseable { combineAutoCloseables(a,b) }, null, l);
}