docs: public CouchDbSamlIdPMetadataDocument merge(final SamlIdPMetadataDocument doc) {
          setId(doc.getId());
          setMetadata(doc.getMetadata());
          setSigningCertificate(doc.getSigningCertificate());
          setSigningKey(doc.getSigningKey());
          setEncryptionCertificate(doc.getEncryptionCertificate());
          setEncryptionKey(doc.getEncryptionKey());
          return this;
      }