code: func LoadWithEnv(conf interface{}, configPaths ...string) error {
  	return loadWithFunc(conf, configPaths, envReplacer, yaml.Unmarshal)
  }
docs: // LoadWithEnv loads YAML files with Env
  // replace {{ env "ENV" }} to os.Getenv("ENV")
  // if you set default value then {{ env "ENV" "default" }}