public Optional<Wei> getBaseFeePerGas() {
    return JsonUtil.getString(genesisRoot, "basefeepergas")
        .map(baseFeeStr -> Wei.of(parseLong("baseFeePerGas", baseFeeStr)));
  }
Gets base fee per gas.

@return the base fee per gas
config/src/main/java/org/hyperledger/besu/config/GenesisConfig.java