Since you wrapped it inside DataParallel, those attributes are no longer available. You should be able to do something like self.model.module.txt_property to access those variables.
Be careful with altering these values though 26:

In each forward,  module  is  replicated  on each device, so any updates to the running module in  forward  will be lost. For example, if  module  has a counter attribute that is incremented in each  forward , it will always stay at the initial value because the update is done on the replicas which are destroyed after  forward .