code: func genLowLevelConfig(conf *serverconfig.Config) (lowLevelConf *Config, err error) {
  	b := &lowBuilder{
  		high: conf,
  		low: jsonconfig.Obj{
  			"prefixes": make(map[string]interface{}),
  		},
  	}
  	return b.build()
  }
docs: // genLowLevelConfig returns a low-level config from a high-level config.