private GenesisConfig readGenesisConfig() {
    GenesisConfig effectiveGenesisFile;
    effectiveGenesisFile =
        network.equals(EPHEMERY)
            ? EphemeryGenesisUpdater.updateGenesis(genesisConfigOverrides)
            : genesisFile != null
                ? GenesisConfig.fromSource(genesisConfigSource(genesisFile))
                : GenesisConfig.fromResource(
                    Optional.ofNullable(network).orElse(MAINNET).getGenesisFile());
    return effectiveGenesisFile.withOverrides(genesisConfigOverrides);
  }
Returns a network interface checker that can be used to validate P2P options.

@return A {@link P2PDiscoveryOptions.NetworkInterfaceChecker} that checks if a network
    interface is available.
app/src/main/java/org/hyperledger/besu/cli/BesuCommand.java