code: func newCAASet(CAAs []*dns.CAA) *CAASet {
  	var filtered CAASet
  
  	for _, caaRecord := range CAAs {
  		switch strings.ToLower(caaRecord.Tag) {
  		case "issue":
  			filtered.Issue = append(filtered.Issue, caaRecord)
  		case "issuewild":
  			filtered.Issuewild = append(filtered.Issuewild, caaRecord)
  		case "iodef":
  			filtered.Iodef = append(filtered.Iodef, caaRecord)
  		default:
  			filtered.Unknown = append(filtered.Unknown, caaRecord)
  		}
  	}
  
  	return &filtered
  }
docs: // Filter CAA records by property