code: func containsString(slice []string, s string, modifier func(s string) string) bool {
  	for _, item := range slice {
  		if item == s {
  			return true
  		}
  		if modifier != nil && modifier(item) == s {
  			return true
  		}
  	}
  	return false
  }
docs: // containsString checks if a given slice of strings contains the provided string.
  // If a modifier func is provided, it is called with the slice item before the comparison.