I am using Google App Engine Python.
I would like to store a simple variable number somewhere, so I can add, deduct and use this number.
All the answers to the question you linked are relevent to you. If you want persistance you will have to create a model. Look at using get_or_insert to fetch/initialize an entity and give your entity a
key_name so that you can keep fetching it easily whenever you need to store your values.
class MyAppData(db.Model): my_number = db.IntegerProperty() # fetch entity whenever you need to store your value data = MyAppData.get_or_insert(key_name='mydata', my_number=1) data.my_number += 1 data.put()
You code does look suspiciously like a counter, and you might want to look at the sharding countering article and the problems that it solves in case they are relevent.