docs: public int andCardinality(Container x) {
      if (this.isEmpty()) {
        return 0;
      } else if (x.isEmpty()) {
        return 0;
      } else {
        if (x instanceof ArrayContainer) {
          return andCardinality((ArrayContainer) x);
        } else if (x instanceof BitmapContainer) {
          return andCardinality((BitmapContainer) x);
        }
        return andCardinality((RunContainer) x);
      }
    }