code: func Map(ss []string, callback func(string) string) []string {
  	newStrings := make([]string, len(ss))
  	for i, s := range ss {
  		newStrings[i] = callback(s)
  	}
  
  	return newStrings
  }
docs: // Map returns a slice containing all the elements of ss
  // after applying the callback function to each one