code: func SortedKeys(m map[string]interface{}) []string {
  	i, sorted := 0, make([]string, len(m))
  	for k := range m {
  		sorted[i] = k
  		i++
  	}
  	sort.Strings(sorted)
  	return sorted
  }
docs: // SortedKeys returns a sorted slice of keys of a map.