code: public static ResourceRecordSet<CERTData> cert(String name, Collection<String> certdata) {
      return new CERTBuilder().name(name).addAll(certdata).build();
    }
docs: creates cert set of {@link denominator.model.rdata.CERTData CERT} records for the specified
  name and ttl.
  
  @param name     ex. {@code denominator.io.}
  @param certdata certdata values ex. {@code [12345 1 1 B33F, 6789 1 1 F00M00]}