code: func StringMap(f func(string) string, data []string) []string {
  	size := len(data)
  	result := make([]string, size, size)
  	for i := 0; i < size; i++ {
  		result[i] = f(data[i])
  	}
  	return result
  }
docs: // Map a function on each element of a slice of strings.