get_by_id method on Model classes in Google App Engine Datastore

Question

I'm unable to workout how you can get objects from the Google App Engine Datastore using get_by_id. Here is the model

from google.appengine.ext import db

class Address(db.Model):
  description = db.StringProperty(multiline=True)
  latitude = db.FloatProperty()
  longitdue = db.FloatProperty()
  date = db.DateTimeProperty(auto_now_add=True)

I can create them, put them, and retrieve them with gql.

address = Address()
address.description = self.request.get('name')
address.latitude = float(self.request.get('latitude'))
address.longitude = float(self.request.get('longitude'))
address.put()

A saved address has values for

>> address.key()
aglndWVzdGJvb2tyDQsSB0FkZHJlc3MYDQw
>> address.key().id()
14

I can find them using the key

from google.appengine.ext import db
address = db.get('aglndWVzdGJvb2tyDQsSB0FkZHJlc3MYDQw')

But can't find them by id

>> from google.appengine.ext import db
>> address = db.Model.get_by_id(14)

The address is None, when I try

>> Address.get_by_id(14)
AttributeError: type object 'Address' has no attribute 'get_by_id'

How can I find by id?

EDIT: It turns out I'm an idiot and was trying find an Address Model in a function called Address. Thanks for your answers, I've marked Brandon as the correct answer as he got in first and demonstrated it should all work.

Solution 1

I just tried it on shell.appspot.com and it seems to work fine:

Google Apphosting/1.0
Python 2.5.2 (r252:60911, Feb 25 2009, 11:04:42) 
[GCC 4.1.0]

>>> class Address(db.Model):
  description = db.StringProperty(multiline=True)
  latitude = db.FloatProperty()
  longitdue = db.FloatProperty()
  date = db.DateTimeProperty(auto_now_add=True)

>>> addy = Address()
>>> addyput = addy.put()
>>> addyput.id()
136522L
>>> Address.get_by_id(136522)
<__main__.Address object at 0xa6b33ae3bf436250>

Solution 2

An app's key is a list of (kind, id_or_name) tuples - for root entities, always only one element long. Thus, an ID alone doesn't identify an entity - the type of entity is also required. When you call db.Model.get_by_id(x), you're asking for the entity with key (Model, x). What you want is to call Address.get_by_id(x), which fetches the entity with key (Address, x).