@Override
  public String defaultValue(final ArgSpec argSpec) {
    loadConfigurationIfNotLoaded();

    // only options can be used in config because a name is needed for the key
    // so we skip default for positional params
    return argSpec.isOption() ? getConfigurationValue(((OptionSpec) argSpec)) : null;
  }
Creates a new TomlConfigurationDefaultProvider from an input stream.

@param commandLine the command line
@param inputStream the input stream
@return a new TomlConfigurationDefaultProvider
app/src/main/java/org/hyperledger/besu/cli/util/TomlConfigurationDefaultProvider.java