'Creates an **"Example"** entity of kind **"NDBConfig"** in the
datastore if the model is empty and raises and error to inform you that
you should populate the model with data.
.. note::
The *Datastore Viewer* in the ``_ah/admin/`` won\'t let you add
properties to a model if there is not an entity with that
property already. Therefore it is a good idea to keep the
**"Example"** entity (which has all possible properties set) in
the datastore.'

@classmethod
def initialize(cls):

    if (not len(cls.query().fetch())):
        example = cls.get_or_insert('Example')
        example.class_ = ('Provider    class    e.g.    ' + '"authomatic.providers.oauth2.Facebook".')
        example.provider_name = 'Your    custom    provider    name    e.g.    "fb".'
        example.consumer_key = 'Consumer    key.'
        example.consumer_secret = 'Consumer    secret'
        example.provider_id = 1
        example.scope = 'coma,    separated,    list,    of,    scopes'
        example.identifier_param = ('Querystring    parameter    for    claimed    ' + 'id.    default    is    "id"')
        example.put()
        raise GAEError('A    NDBConfig    data    model    was    created!    Go    to    Datastore    Viewer    in    your    dashboard    and    populate    it    with    data!')
