@Override
  public OptionalLong getPetersburgBlockNumber() {
    final OptionalLong petersburgBlock = getOptionalLong("petersburgblock");
    final OptionalLong constantinopleFixBlock = getOptionalLong("constantinoplefixblock");
    if (constantinopleFixBlock.isPresent()) {
      if (petersburgBlock.isPresent()) {
        throw new RuntimeException(
            "Genesis files cannot specify both petersburgBlock and constantinopleFixBlock.");
      }
      return constantinopleFixBlock;
    }
    return petersburgBlock;
  }
Instantiates a new Json genesis config options.

@param maybeConfig the optional config
@param configOverrides the config overrides map
@param transitionsConfig the transitions configuration
config/src/main/java/org/hyperledger/besu/config/JsonGenesisConfigOptions.java