private boolean hasDuplicateAuthors(
      final Collection<SignedData<RoundChangePayload>> roundChangeMsgs) {
    final long distinctAuthorCount =
        roundChangeMsgs.stream().map(SignedData::getAuthor).distinct().count();

    if (distinctAuthorCount != roundChangeMsgs.size()) {
      LOG.info("Invalid RoundChangeCertificate, multiple RoundChanges from the same author.");
      return true;
    }
    return false;
  }
Validate round change messages and ensure target round matches root boolean.

@param expectedRound the expected round
@param roundChangeCert the round change cert
@return the boolean
consensus/ibft/src/main/java/org/hyperledger/besu/consensus/ibft/validation/RoundChangeCertificateValidator.java