We are using this code to get all blocks:

var contentTypeRepository = ServiceLocator.Current.GetInstance<IContentTypeRepository>();
var contentModelUsage = ServiceLocator.Current.GetInstance<IContentModelUsage>();
var blockType = contentTypeRepository.Load<CertificationSubStepBlock>();
var allBlocks = contentModelUsage.ListContentOfContentType(blockType);

But we need just blocks which are published, and the code above retreives obsolate blocks from the trash too.

Can anybody help me with this?

Thanks!