@Override
  public boolean contains(int bitIndex) {
    if (bitIndex < bitIndexBase || bitIndexBase < 0) return false;
    bitIndex -= bitIndexBase;
    int wordIndex = bitIndex >> SHIFT;
    boolean result = false;
    if (wordIndex < bitSlots.length) {
      result = (bitSlots[wordIndex] & (1L << (bitIndex & MASK))) != 0;
    }

    return result;
  }
@Override
  public boolean contains(int bitIndex)