How can implement model like class in python

I have been working with django and appengine-python frameworks. But I still can't understand its model implementation.

For example:

In Django

class user(models.Model):
    name = models.CharField()
    age = models.IntegerField()

after this for saving the model

u  = user(name="foo",age=23)
u.save()

On Appengine python

class user(ndb.Model):
     name = ndb.StringProperty()
     age = ndb.IntegerProperty()

after this is done for saving to datastore

u =user()
u.name = "foo"
u.age = 23
u.put()

I know this kind of implementation is achieved through inheritance but the thing that i can't understand is how are they getting value of the properties for saving through put or save method.

what my question is.

suppose i have base class b with which i derive a class c and class b already has a method put which gets the attribute information from c to does some specific process. how can i implement this kind of design in python ?

Kindly help me out.