docs: private <T> MappedClass validateSave(final T entity) {
          if (entity == null) {
              throw new UpdateException("Can not persist a null entity");
          }
  
          final MappedClass mc = mapper.getMappedClass(entity);
          if (mc.getAnnotation(NotSaved.class) != null) {
              throw new MappingException(format("Entity type: %s is marked as NotSaved which means you should not try to save it!",
                  mc.getClazz().getName()));
          }
          return mc;
      }