public Config Configure(Config defaultConfig, Config[] existingConfigs) {
existingConfigs = existingConfigs ?? new Config[0];
if (existingConfigs.Any((cfg) => cfg.name == defaultConfig.name))
throw new InvalidOperationException(string.Format(ExceptionStrings.instance.sErrorNameNotUnique, defaultConfig.name));
return OnConfigure(defaultConfig, existingConfigs);
}