'Delete entity from datastore.
Attempts to delete using the key_name stored on the object, whether or
not the given key is in the datastore.'

def _delete_entity(self):

    if self._is_ndb():
        _NDB_KEY(self._model, self._key_name).delete()
    else:
        entity_key = db.Key.from_path(self._model.kind(), self._key_name)
        db.delete(entity_key)
