@Override
  protected BlockParameter blockParameter(final JsonRpcRequestContext request) {
    try {
      return request.getRequiredParameter(0, BlockParameter.class);
    } catch (JsonRpcParameterException e) {
      throw new InvalidJsonRpcParameters(
          "Invalid block parameter (index 0)", RpcErrorType.INVALID_BLOCK_PARAMS, e);
    }
  }
Instantiates a new Qbft get validators by block number.

@param blockchainQueries the blockchain queries
@param validatorProvider the validator provider
consensus/qbft/src/main/java/org/hyperledger/besu/consensus/qbft/jsonrpc/methods/QbftGetValidatorsByBlockNumber.java