code: void merge(Settings other) {
      for (int i = 0; i < COUNT; i++) {
        if (!other.isSet(i)) continue;
        set(i, other.flags(i), other.get(i));
      }
    }
docs: Writes {@code other} into this. If any setting is populated by this and
  {@code other}, the value and flags from {@code other} will be kept.