@NotNull BitString or(BitString other) {
      long orBits = myBits | other.myBits;
      // 1 | ? = ? | 1 = 1; 0 | 0 = 0; ? | 0 = 0 | ? = ? | ? = ?
      long orMask = ((myMask ^ myBits) & (other.myMask ^ other.myBits)) | orBits;
      return new BitString(orBits, orMask);
    }
@NotNull BitString or(BitString other)