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".