You can not create an operation for Production "%(production)s". We can not found any work center for Operation "%(operation)s". Production "%(production)s" can not be done because their operation "%(operation)s" is not done.' You can not finish an operation without create a purchase on Purchase request "%(request)s". You can not finish an operation without finish purchase "%(purchase)s". Operation "%(operation)s" on Production "%(production)s" already has a purchase request".