code: func (o *OsFetcher) GetAll(key string) []string {
  	if v, ok := o.Get(key); ok {
  		return []string{v}
  	}
  	return make([]string, 0)
  }
docs: // GetAll implements the `config.Fetcher.GetAll` method by returning, at most, a
  // 1-ary set containing the result of `config.OsFetcher.Get()`.