code: public static Mapping<UUID> uuid(Constraint... constraints) {
          return new FieldMapping(
                  InputMode.SINGLE,
                  mkSimpleConverter(s ->
                      isEmptyStr(s) ? null : UUID.fromString(s)
                  ), new MappingMeta(MAPPING_UUID, UUID.class)
              ).constraint(checking(UUID::fromString, "error.uuid", true))
                  .constraint(constraints);
          }
docs: (convert to UUID) mapping
  @param constraints constraints
  @return new created mapping