Cond<T> append(Condition<? super T> impl) {
      Cond<T> result = new Cond<>(impl, null);
      for (Cond<T> o : toArray(true)) {
        result = new Cond<>(o.impl, result);
      }
      return result;
    }
Cond<T> append(Condition<? super T> impl)