private OptionalLong getOptionalLong(final String key) {
    if (configOverrides.containsKey(key)) {
      final String value = configOverrides.get(key);
      return value == null || value.isEmpty()
          ? OptionalLong.empty()
          : OptionalLong.of(Long.valueOf(configOverrides.get(key), 10));
    } else {
      return JsonUtil.getLong(configRoot, key);
    }
  }
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